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2017-07-09Merge branch 'locking-urgent-for-linus' of ↵Linus Torvalds2-2/+3
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fixes from Thomas Gleixner: - Fix the EINTR logic in rwsem-spinlock to avoid double locking by a writer and a reader - Add a missing include to qspinlocks * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/qspinlock: Explicitly include asm/prefetch.h locking/rwsem-spinlock: Fix EINTR branch in __down_write_common()
2017-07-08Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-nextLinus Torvalds1-0/+1
Pull sparc updates from David Miller: 1) Queued spinlocks and rwlocks for sparc64, from Babu Moger. 2) Some const'ification from Arvind Yadav. 3) LDC/VIO driver infrastructure changes to facilitate future upcoming drivers, from Jag Raman. 4) Initialize sched_clock() et al. early so that the initial printk timestamps are all done while the implementation is available and functioning. From Pavel Tatashin. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next: (38 commits) sparc: kernel: pmc: make of_device_ids const. sparc64: fix typo in property sparc64: add port_id to VIO device metadata sparc64: Enhance search for VIO device in MDESC sparc64: enhance VIO device probing sparc64: check if a client is allowed to register for MDESC notifications sparc64: remove restriction on VIO device name size sparc64: refactor code to obtain cfg_handle property from MDESC sparc64: add MDESC node name property to VIO device metadata sparc64: mdesc: use __GFP_REPEAT action modifier for VM allocation sparc64: expand MDESC interface sparc64: skip handshake for LDC channels in RAW mode sparc64: specify the device class in VIO version info. packet sparc64: ensure VIO operations are defined while being used sparc: kernel: apc: make of_device_ids const sparc/time: make of_device_ids const sparc64: broken %tick frequency on spitfire cpus sparc64: use prom interface to get %stick frequency sparc64: optimize functions that access tick sparc64: add hot-patched and inlined get_tick() ...
2017-07-08locking/qspinlock: Explicitly include asm/prefetch.hStafford Horne1-0/+1
In architectures that use qspinlock, like x86, prefetch is loaded indirectly via the asm/qspinlock.h include. On other architectures, like OpenRISC, which may want to use asm-generic/qspinlock.h the built will fail without the asm/prefetch.h include. Fix this by including directly. Signed-off-by: Stafford Horne <shorne@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170707195658.23840-1-shorne@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-06mm: update callers to use HASH_ZERO flagPavel Tatashin1-1/+2
Update dcache, inode, pid, mountpoint, and mount hash tables to use HASH_ZERO, and remove initialization after allocations. In case of places where HASH_EARLY was used such as in __pv_init_lock_hash the zeroed hash table was already assumed, because memblock zeroes the memory. CPU: SPARC M6, Memory: 7T Before fix: Dentry cache hash table entries: 1073741824 Inode-cache hash table entries: 536870912 Mount-cache hash table entries: 16777216 Mountpoint-cache hash table entries: 16777216 ftrace: allocating 20414 entries in 40 pages Total time: 11.798s After fix: Dentry cache hash table entries: 1073741824 Inode-cache hash table entries: 536870912 Mount-cache hash table entries: 16777216 Mountpoint-cache hash table entries: 16777216 ftrace: allocating 20414 entries in 40 pages Total time: 3.198s CPU: Intel Xeon E5-2630, Memory: 2.2T: Before fix: Dentry cache hash table entries: 536870912 Inode-cache hash table entries: 268435456 Mount-cache hash table entries: 8388608 Mountpoint-cache hash table entries: 8388608 CPU: Physical Processor ID: 0 Total time: 3.245s After fix: Dentry cache hash table entries: 536870912 Inode-cache hash table entries: 268435456 Mount-cache hash table entries: 8388608 Mountpoint-cache hash table entries: 8388608 CPU: Physical Processor ID: 0 Total time: 3.244s Link: http://lkml.kernel.org/r/1488432825-92126-4-git-send-email-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Babu Moger <babu.moger@oracle.com> Cc: David Miller <davem@davemloft.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-05locking/rwsem-spinlock: Fix EINTR branch in __down_write_common()Kirill Tkhai1-2/+2
If a writer could been woken up, the above branch if (sem->count == 0) break; would have moved us to taking the sem. So, it's not the time to wake a writer now, and only readers are allowed now. Thus, 0 must be passed to __rwsem_do_wake(). Next, __rwsem_do_wake() wakes readers unconditionally. But we mustn't do that if the sem is owned by writer in the moment. Otherwise, writer and reader own the sem the same time, which leads to memory corruption in callers. rwsem-xadd.c does not need that, as: 1) the similar check is made lockless there, 2) in __rwsem_mark_wake::try_reader_grant we test, that sem is not owned by writer. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <stable@vger.kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Niklas Cassel <niklas.cassel@axis.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 17fcbd590d0c "locking/rwsem: Fix down_write_killable() for CONFIG_RWSEM_GENERIC_SPINLOCK=y" Link: http://lkml.kernel.org/r/149762063282.19811.9129615532201147826.stgit@localhost.localdomain Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-03Merge tag 'docs-4.13' of git://git.lwn.net/linuxLinus Torvalds1-3/+3
Pull documentation updates from Jonathan Corbet: "There has been a fair amount of activity in the docs tree this time around. Highlights include: - Conversion of a bunch of security documentation into RST - The conversion of the remaining DocBook templates by The Amazing Mauro Machine. We can now drop the entire DocBook build chain. - The usual collection of fixes and minor updates" * tag 'docs-4.13' of git://git.lwn.net/linux: (90 commits) scripts/kernel-doc: handle DECLARE_HASHTABLE Documentation: atomic_ops.txt is core-api/atomic_ops.rst Docs: clean up some DocBook loose ends Make the main documentation title less Geocities Docs: Use kernel-figure in vidioc-g-selection.rst Docs: fix table problems in ras.rst Docs: Fix breakage with Sphinx 1.5 and upper Docs: Include the Latex "ifthen" package doc/kokr/howto: Only send regression fixes after -rc1 docs-rst: fix broken links to dynamic-debug-howto in kernel-parameters doc: Document suitability of IBM Verse for kernel development Doc: fix a markup error in coding-style.rst docs: driver-api: i2c: remove some outdated information Documentation: DMA API: fix a typo in a function name Docs: Insert missing space to separate link from text doc/ko_KR/memory-barriers: Update control-dependencies example Documentation, kbuild: fix typo "minimun" -> "minimum" docs: Fix some formatting issues in request-key.rst doc: ReSTify keys-trusted-encrypted.txt doc: ReSTify keys-request-key.txt ...
2017-07-03Merge branch 'locking-core-for-linus' of ↵Linus Torvalds4-10/+37
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "The main changes in this cycle were: - Add CONFIG_REFCOUNT_FULL=y to allow the disabling of the 'full' (robustness checked) refcount_t implementation with slightly lower runtime overhead. (Kees Cook) The lighter weight variant is the default. The two variants use the same API. Having this variant was a precondition by some maintainers to merge refcount_t cleanups. - Add lockdep support for rtmutexes (Peter Zijlstra) - liblockdep fixes and improvements (Sasha Levin, Ben Hutchings) - ... misc fixes and improvements" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (30 commits) locking/refcount: Remove the half-implemented refcount_sub() API locking/refcount: Create unchecked atomic_t implementation locking/rtmutex: Don't initialize lockdep when not required locking/selftest: Add RT-mutex support locking/selftest: Remove the bad unlock ordering test rt_mutex: Add lockdep annotations MAINTAINERS: Claim atomic*_t maintainership locking/x86: Remove the unused atomic_inc_short() methd tools/lib/lockdep: Remove private kernel headers tools/lib/lockdep: Hide liblockdep output from test results tools/lib/lockdep: Add dummy current_gfp_context() tools/include: Add IS_ERR_OR_NULL to err.h tools/lib/lockdep: Add empty __is_[module,kernel]_percpu_address tools/lib/lockdep: Include err.h tools/include: Add (mostly) empty include/linux/sched/mm.h tools/lib/lockdep: Use LDFLAGS tools/lib/lockdep: Remove double-quotes from soname tools/lib/lockdep: Fix object file paths used in an out-of-tree build tools/lib/lockdep: Fix compilation for 4.11 tools/lib/lockdep: Don't mix fd-based and stream IO ...
2017-06-20locking/rtmutex: Don't initialize lockdep when not requiredLevin, Alexander (Sasha Levin)1-1/+2
pi_mutex isn't supposed to be tracked by lockdep, but just passing NULLs for name and key will cause lockdep to spew a warning and die, which is not what we want it to do. Skip lockdep initialization if the caller passed NULLs for name and key, suggesting such initialization isn't desired. Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: f5694788ad8d ("rt_mutex: Add lockdep annotations") Link: http://lkml.kernel.org/r/20170618140548.4763-1-alexander.levin@verizon.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-06-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparcDavid S. Miller1-6/+18
2017-06-08rcu: Remove the now-obsolete PROVE_RCU_REPEATEDLY Kconfig optionPaul E. McKenney1-4/+0
The PROVE_RCU_REPEATEDLY Kconfig option was initially added due to the volume of messages from PROVE_RCU: Doing just one per boot would have required excessive numbers of boots to locate them all. However, PROVE_RCU messages are now relatively rare, so there is no longer any reason to need more than one such message per boot. This commit therefore removes the PROVE_RCU_REPEATEDLY Kconfig option. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org>
2017-06-08lockdep: Use consistent printing primitivesPaul E. McKenney1-86/+86
Commit a5dd63efda3d ("lockdep: Use "WARNING" tag on lockdep splats") substituted pr_warn() for printk() in places called out by Dmitry Vyukov. However, this resulted in an ugly mix of pr_warn() and printk(). This commit therefore changes printk() to pr_warn() or pr_cont(), depending on the absence or presence of KERN_CONT. This is done in all functions that had printk() changed to pr_warn() by the aforementioned commit. Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2017-06-08rt_mutex: Add lockdep annotationsPeter Zijlstra4-10/+36
Now that (PI) futexes have their own private RT-mutex interface and implementation we can easily add lockdep annotations to the existing RT-mutex interface. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-25kernel/locking: Fix compile error with qrwlock.cBabu Moger1-0/+1
Saw these compile errors on SPARC when queued rwlock feature is enabled. CC kernel/locking/qrwlock.o kernel/locking/qrwlock.c: In function ‘queued_read_lock_slowpath’: kernel/locking/qrwlock.c:89: error: implicit declaration of function ‘arch_spin_lock’ kernel/locking/qrwlock.c:102: error: implicit declaration of function ‘arch_spin_unlock’ make[4]: *** [kernel/locking/qrwlock.o] Error 1 Include spinlock.h in qrwlock.c to fix it. Signed-off-by: Babu Moger <babu.moger@oracle.com> Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com> Reviewed-by: Vijay Kumar <vijay.ac.kumar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-22futex,rt_mutex: Fix rt_mutex_cleanup_proxy_lock()Peter Zijlstra1-6/+18
Markus reported that the glibc/nptl/tst-robustpi8 test was failing after commit: cfafcd117da0 ("futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()") The following trace shows the problem: ld-linux-x86-64-2161 [019] .... 410.760971: SyS_futex: 00007ffbeb76b028: 80000875 op=FUTEX_LOCK_PI ld-linux-x86-64-2161 [019] ...1 410.760972: lock_pi_update_atomic: 00007ffbeb76b028: curval=80000875 uval=80000875 newval=80000875 ret=0 ld-linux-x86-64-2165 [011] .... 410.760978: SyS_futex: 00007ffbeb76b028: 80000875 op=FUTEX_UNLOCK_PI ld-linux-x86-64-2165 [011] d..1 410.760979: do_futex: 00007ffbeb76b028: curval=80000875 uval=80000875 newval=80000871 ret=0 ld-linux-x86-64-2165 [011] .... 410.760980: SyS_futex: 00007ffbeb76b028: 80000871 ret=0000 ld-linux-x86-64-2161 [019] .... 410.760980: SyS_futex: 00007ffbeb76b028: 80000871 ret=ETIMEDOUT Task 2165 does an UNLOCK_PI, assigning the lock to the waiter task 2161 which then returns with -ETIMEDOUT. That wrecks the lock state, because now the owner isn't aware it acquired the lock and removes the pending robust list entry. If 2161 is killed, the robust list will not clear out this futex and the subsequent acquire on this futex will then (correctly) result in -ESRCH which is unexpected by glibc, triggers an internal assertion and dies. Task 2161 Task 2165 rt_mutex_wait_proxy_lock() timeout(); /* T2161 is still queued in the waiter list */ return -ETIMEDOUT; futex_unlock_pi() spin_lock(hb->lock); rtmutex_unlock() remove_rtmutex_waiter(T2161); mark_lock_available(); /* Make the next waiter owner of the user space side */ futex_uval = 2161; spin_unlock(hb->lock); spin_lock(hb->lock); rt_mutex_cleanup_proxy_lock() if (rtmutex_owner() !== current) ... return FAIL; .... return -ETIMEOUT; This means that rt_mutex_cleanup_proxy_lock() needs to call try_to_take_rt_mutex() so it can take over the rtmutex correctly which was assigned by the waker. If the rtmutex is owned by some other task then this call is harmless and just confirmes that the waiter is not able to acquire it. While there, fix what looks like a merge error which resulted in rt_mutex_cleanup_proxy_lock() having two calls to fixup_rt_mutex_waiters() and rt_mutex_wait_proxy_lock() not having any. Both should have one, since both potentially touch the waiter list. Fixes: 38d589f2fd08 ("futex,rt_mutex: Restructure rt_mutex_finish_proxy_lock()") Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Bug-Spotted-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Florian Weimer <fweimer@redhat.com> Cc: Darren Hart <dvhart@infradead.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Markus Trippelsdorf <markus@trippelsdorf.de> Link: http://lkml.kernel.org/r/20170519154850.mlomgdsd26drq5j6@hirez.programming.kicks-ass.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-05-18Merge remote-tracking branch 'mauro-exp/docbook3' into death-to-docbookJonathan Corbet1-3/+3
Mauro says: This patch series convert the remaining DocBooks to ReST. The first version was originally send as 3 patch series: [PATCH 00/36] Convert DocBook documents to ReST [PATCH 0/5] Convert more books to ReST [PATCH 00/13] Get rid of DocBook The lsm book was added as if it were a text file under Documentation. The plan is to merge it with another file under Documentation/security, after both this series and a security Documentation patch series gets merged. It also adjusts some Sphinx-pedantic errors/warnings on some kernel-doc markups. I also added some patches here to add PDF output for all existing ReST books.
2017-05-16mutex, futex: adjust kernel-doc markups to generate ReSTMauro Carvalho Chehab1-3/+3
There are a few issues on some kernel-doc markups that was causing troubles with kernel-doc output on ReST format: ./kernel/futex.c:492: WARNING: Inline emphasis start-string without end-string. ./kernel/futex.c:1264: WARNING: Block quote ends without a blank line; unexpected unindent. ./kernel/futex.c:1721: WARNING: Block quote ends without a blank line; unexpected unindent. ./kernel/futex.c:2338: WARNING: Block quote ends without a blank line; unexpected unindent. ./kernel/futex.c:2426: WARNING: Block quote ends without a blank line; unexpected unindent. ./kernel/futex.c:2899: WARNING: Block quote ends without a blank line; unexpected unindent. ./kernel/futex.c:2972: WARNING: Block quote ends without a blank line; unexpected unindent. Fix them. No functional changes. Acked-by: Darren Hart (VMware) <dvhart@infradead.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-05-10Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds2-47/+48
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "The main changes are: - Debloat RCU headers - Parallelize SRCU callback handling (plus overlapping patches) - Improve the performance of Tree SRCU on a CPU-hotplug stress test - Documentation updates - Miscellaneous fixes" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (74 commits) rcu: Open-code the rcu_cblist_n_lazy_cbs() function rcu: Open-code the rcu_cblist_n_cbs() function rcu: Open-code the rcu_cblist_empty() function rcu: Separately compile large rcu_segcblist functions srcu: Debloat the <linux/rcu_segcblist.h> header srcu: Adjust default auto-expediting holdoff srcu: Specify auto-expedite holdoff time srcu: Expedite first synchronize_srcu() when idle srcu: Expedited grace periods with reduced memory contention srcu: Make rcutorture writer stalls print SRCU GP state srcu: Exact tracking of srcu_data structures containing callbacks srcu: Make SRCU be built by default srcu: Fix Kconfig botch when SRCU not selected rcu: Make non-preemptive schedule be Tasks RCU quiescent state srcu: Expedite srcu_schedule_cbs_snp() callback invocation srcu: Parallelize callback handling kvm: Move srcu_struct fields to end of struct kvm rcu: Fix typo in PER_RCU_NODE_PERIOD header comment rcu: Use true/false in assignment to bool rcu: Use bool value directly ...
2017-05-03Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-2/+9
Merge misc updates from Andrew Morton: - a few misc things - most of MM - KASAN updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (102 commits) kasan: separate report parts by empty lines kasan: improve double-free report format kasan: print page description after stacks kasan: improve slab object description kasan: change report header kasan: simplify address description logic kasan: change allocation and freeing stack traces headers kasan: unify report headers kasan: introduce helper functions for determining bug type mm: hwpoison: call shake_page() after try_to_unmap() for mlocked page mm: hwpoison: call shake_page() unconditionally mm/swapfile.c: fix swap space leak in error path of swap_free_entries() mm/gup.c: fix access_ok() argument type mm/truncate: avoid pointless cleancache_invalidate_inode() calls. mm/truncate: bail out early from invalidate_inode_pages2_range() if mapping is empty fs/block_dev: always invalidate cleancache in invalidate_bdev() fs: fix data invalidation in the cleancache during direct IO zram: reduce load operation in page_same_filled zram: use zram_free_page instead of open-coded zram: introduce zram data accessor ...
2017-05-03mm: introduce memalloc_nofs_{save,restore} APIMichal Hocko1-3/+3
GFP_NOFS context is used for the following 5 reasons currently: - to prevent from deadlocks when the lock held by the allocation context would be needed during the memory reclaim - to prevent from stack overflows during the reclaim because the allocation is performed from a deep context already - to prevent lockups when the allocation context depends on other reclaimers to make a forward progress indirectly - just in case because this would be safe from the fs POV - silence lockdep false positives Unfortunately overuse of this allocation context brings some problems to the MM. Memory reclaim is much weaker (especially during heavy FS metadata workloads), OOM killer cannot be invoked because the MM layer doesn't have enough information about how much memory is freeable by the FS layer. In many cases it is far from clear why the weaker context is even used and so it might be used unnecessarily. We would like to get rid of those as much as possible. One way to do that is to use the flag in scopes rather than isolated cases. Such a scope is declared when really necessary, tracked per task and all the allocation requests from within the context will simply inherit the GFP_NOFS semantic. Not only this is easier to understand and maintain because there are much less problematic contexts than specific allocation requests, this also helps code paths where FS layer interacts with other layers (e.g. crypto, security modules, MM etc...) and there is no easy way to convey the allocation context between the layers. Introduce memalloc_nofs_{save,restore} API to control the scope of GFP_NOFS allocation context. This is basically copying memalloc_noio_{save,restore} API we have for other restricted allocation context GFP_NOIO. The PF_MEMALLOC_NOFS flag already exists and it is just an alias for PF_FSTRANS which has been xfs specific until recently. There are no more PF_FSTRANS users anymore so let's just drop it. PF_MEMALLOC_NOFS is now checked in the MM layer and drops __GFP_FS implicitly same as PF_MEMALLOC_NOIO drops __GFP_IO. memalloc_noio_flags is renamed to current_gfp_context because it now cares about both PF_MEMALLOC_NOFS and PF_MEMALLOC_NOIO contexts. Xfs code paths preserve their semantic. kmem_flags_convert() doesn't need to evaluate the flag anymore. This patch shouldn't introduce any functional changes. Let's hope that filesystems will drop direct GFP_NOFS (resp. ~__GFP_FS) usage as much as possible and only use a properly documented memalloc_nofs_{save,restore} checkpoints where they are appropriate. [akpm@linux-foundation.org: fix comment typo, reflow comment] Link: http://lkml.kernel.org/r/20170306131408.9828-5-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Chris Mason <clm@fb.com> Cc: David Sterba <dsterba@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Brian Foster <bfoster@redhat.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Nikolay Borisov <nborisov@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03lockdep: allow to disable reclaim lockup detectionMichal Hocko1-0/+4
The current implementation of the reclaim lockup detection can lead to false positives and those even happen and usually lead to tweak the code to silence the lockdep by using GFP_NOFS even though the context can use __GFP_FS just fine. See http://lkml.kernel.org/r/20160512080321.GA18496@dastard as an example. ================================= [ INFO: inconsistent lock state ] 4.5.0-rc2+ #4 Tainted: G O --------------------------------- inconsistent {RECLAIM_FS-ON-R} -> {IN-RECLAIM_FS-W} usage. kswapd0/543 [HC0[0]:SC0[0]:HE1:SE1] takes: (&xfs_nondir_ilock_class){++++-+}, at: xfs_ilock+0x177/0x200 [xfs] {RECLAIM_FS-ON-R} state was registered at: mark_held_locks+0x79/0xa0 lockdep_trace_alloc+0xb3/0x100 kmem_cache_alloc+0x33/0x230 kmem_zone_alloc+0x81/0x120 [xfs] xfs_refcountbt_init_cursor+0x3e/0xa0 [xfs] __xfs_refcount_find_shared+0x75/0x580 [xfs] xfs_refcount_find_shared+0x84/0xb0 [xfs] xfs_getbmap+0x608/0x8c0 [xfs] xfs_vn_fiemap+0xab/0xc0 [xfs] do_vfs_ioctl+0x498/0x670 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x12/0x6f CPU0 ---- lock(&xfs_nondir_ilock_class); <Interrupt> lock(&xfs_nondir_ilock_class); *** DEADLOCK *** 3 locks held by kswapd0/543: stack backtrace: CPU: 0 PID: 543 Comm: kswapd0 Tainted: G O 4.5.0-rc2+ #4 Call Trace: lock_acquire+0xd8/0x1e0 down_write_nested+0x5e/0xc0 xfs_ilock+0x177/0x200 [xfs] xfs_reflink_cancel_cow_range+0x150/0x300 [xfs] xfs_fs_evict_inode+0xdc/0x1e0 [xfs] evict+0xc5/0x190 dispose_list+0x39/0x60 prune_icache_sb+0x4b/0x60 super_cache_scan+0x14f/0x1a0 shrink_slab.part.63.constprop.79+0x1e9/0x4e0 shrink_zone+0x15e/0x170 kswapd+0x4f1/0xa80 kthread+0xf2/0x110 ret_from_fork+0x3f/0x70 To quote Dave: "Ignoring whether reflink should be doing anything or not, that's a "xfs_refcountbt_init_cursor() gets called both outside and inside transactions" lockdep false positive case. The problem here is lockdep has seen this allocation from within a transaction, hence a GFP_NOFS allocation, and now it's seeing it in a GFP_KERNEL context. Also note that we have an active reference to this inode. So, because the reclaim annotations overload the interrupt level detections and it's seen the inode ilock been taken in reclaim ("interrupt") context, this triggers a reclaim context warning where it thinks it is unsafe to do this allocation in GFP_KERNEL context holding the inode ilock..." This sounds like a fundamental problem of the reclaim lock detection. It is really impossible to annotate such a special usecase IMHO unless the reclaim lockup detection is reworked completely. Until then it is much better to provide a way to add "I know what I am doing flag" and mark problematic places. This would prevent from abusing GFP_NOFS flag which has a runtime effect even on configurations which have lockdep disabled. Introduce __GFP_NOLOCKDEP flag which tells the lockdep gfp tracking to skip the current allocation request. While we are at it also make sure that the radix tree doesn't accidentaly override tags stored in the upper part of the gfp_mask. Link: http://lkml.kernel.org/r/20170306131408.9828-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Chris Mason <clm@fb.com> Cc: David Sterba <dsterba@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Brian Foster <bfoster@redhat.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03lockdep: teach lockdep about memalloc_noio_saveNikolay Borisov1-1/+4
Patch series "scope GFP_NOFS api", v5. This patch (of 7): Commit 21caf2fc1931 ("mm: teach mm by current context info to not do I/O during memory allocation") added the memalloc_noio_(save|restore) functions to enable people to modify the MM behavior by disabling I/O during memory allocation. This was further extended in commit 934f3072c17c ("mm: clear __GFP_FS when PF_MEMALLOC_NOIO is set"). memalloc_noio_* functions prevent allocation paths recursing back into the filesystem without explicitly changing the flags for every allocation site. However, lockdep hasn't been keeping up with the changes and it entirely misses handling the memalloc_noio adjustments. Instead, it is left to the callers of __lockdep_trace_alloc to call the function after they have shaven the respective GFP flags which can lead to false positives: ================================= [ INFO: inconsistent lock state ] 4.10.0-nbor #134 Not tainted --------------------------------- inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage. fsstress/3365 [HC0[0]:SC0[0]:HE1:SE1] takes: (&xfs_nondir_ilock_class){++++?.}, at: xfs_ilock+0x141/0x230 {IN-RECLAIM_FS-W} state was registered at: __lock_acquire+0x62a/0x17c0 lock_acquire+0xc5/0x220 down_write_nested+0x4f/0x90 xfs_ilock+0x141/0x230 xfs_reclaim_inode+0x12a/0x320 xfs_reclaim_inodes_ag+0x2c8/0x4e0 xfs_reclaim_inodes_nr+0x33/0x40 xfs_fs_free_cached_objects+0x19/0x20 super_cache_scan+0x191/0x1a0 shrink_slab+0x26f/0x5f0 shrink_node+0xf9/0x2f0 kswapd+0x356/0x920 kthread+0x10c/0x140 ret_from_fork+0x31/0x40 irq event stamp: 173777 hardirqs last enabled at (173777): __local_bh_enable_ip+0x70/0xc0 hardirqs last disabled at (173775): __local_bh_enable_ip+0x37/0xc0 softirqs last enabled at (173776): _xfs_buf_find+0x67a/0xb70 softirqs last disabled at (173774): _xfs_buf_find+0x5db/0xb70 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&xfs_nondir_ilock_class); <Interrupt> lock(&xfs_nondir_ilock_class); *** DEADLOCK *** 4 locks held by fsstress/3365: #0: (sb_writers#10){++++++}, at: mnt_want_write+0x24/0x50 #1: (&sb->s_type->i_mutex_key#12){++++++}, at: vfs_setxattr+0x6f/0xb0 #2: (sb_internal#2){++++++}, at: xfs_trans_alloc+0xfc/0x140 #3: (&xfs_nondir_ilock_class){++++?.}, at: xfs_ilock+0x141/0x230 stack backtrace: CPU: 0 PID: 3365 Comm: fsstress Not tainted 4.10.0-nbor #134 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: kmem_cache_alloc_node_trace+0x3a/0x2c0 vm_map_ram+0x2a1/0x510 _xfs_buf_map_pages+0x77/0x140 xfs_buf_get_map+0x185/0x2a0 xfs_attr_rmtval_set+0x233/0x430 xfs_attr_leaf_addname+0x2d2/0x500 xfs_attr_set+0x214/0x420 xfs_xattr_set+0x59/0xb0 __vfs_setxattr+0x76/0xa0 __vfs_setxattr_noperm+0x5e/0xf0 vfs_setxattr+0xae/0xb0 setxattr+0x15e/0x1a0 path_setxattr+0x8f/0xc0 SyS_lsetxattr+0x11/0x20 entry_SYSCALL_64_fastpath+0x23/0xc6 Let's fix this by making lockdep explicitly do the shaving of respective GFP flags. Fixes: 934f3072c17c ("mm: clear __GFP_FS when PF_MEMALLOC_NOIO is set") Link: http://lkml.kernel.org/r/20170306131408.9828-2-mhocko@kernel.org Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Chris Mason <clm@fb.com> Cc: David Sterba <dsterba@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Brian Foster <bfoster@redhat.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03Merge tag 'drm-for-v4.12' of git://people.freedesktop.org/~airlied/linuxLinus Torvalds1-0/+2
Pull drm u pdates from Dave Airlie: "This is the main drm pull request for v4.12. Apart from two fixes pulls, everything should have been in drm-next for at least 2 weeks. The biggest thing in here is AMD released the public headers for their upcoming VEGA GPUs. These as always are quite a sizeable chunk of header files. They've also added initial non-display support for those GPUs, though they aren't available in production yet. Otherwise it's pretty much normal. New bridge drivers: - megachips-stdpxxxx-ge-b850v3-fw LVDS->DP++ - generic LVDS bridge support. Core: - Displayport link train failure reporting to userspace - debugfs interface cleaned up - subsystem TODO in kerneldoc now - Extended fbdev support (flipping and vblank wait) - drm_platform removed - EDP CRC support in helper - HF-VSDB SCDC support in EDID parser - Lots of code cleanups and header extraction - Thunderbolt external GPU awareness - Atomic helper improvements - Documentation improvements panel: - Sitronix and Samsung new panel support amdgpu: - Preliminary vega10 support - Multi-level page table support - GPU sensor support for userspace - PRT support for sparse buffers - SR-IOV improvements - Non-contig VRAM CPU mapping i915: - Atomic modesetting enabled by default on Gen5+ - LSPCON improvements - Atomic state handling for cdclk - GPU reset improvements - In-kernel unit tests - Geminilake improvements and color manager support - Designware i2c fixes - vblank evasion improvements - Hotplug safe connector iterators - GVT scheduler QoS support - GVT Kabylake support nouveau: - Acceleration support for Pascal (GP10x). - Rearchitecture of code handling proprietary signed firmware - Fix GTX 970 with odd MMU configuration - GP10B support - GP107 acceleration support vmwgfx: - Atomic modesetting support for vmwgfx omapdrm: - Support for render nodes - Refactor omapdss code - Fix some probe ordering issues - Fix too dark RGB565 rendering sunxi: - prelim rework for multiple pipes. mali-dp: - Color management support - Plane scaling - Power management improvements imx-drm: - Prefetch Resolve Engine/Gasket on i.MX6QP - Deferred plane disabling - Separate alpha support mediatek: - Mediatek SoC MT2701 support rcar-du: - Gen3 HDMI support msm: - 4k support for newer chips - OPP bindings for gpu - prep work for per-process pagetables vc4: - HDMI audio support - fixes qxl: - minor fixes. dw-hdmi: - PHY improvements - CSC fixes - Amlogic GX SoC support" * tag 'drm-for-v4.12' of git://people.freedesktop.org/~airlied/linux: (1778 commits) drm/nouveau/fb/gf100-: Fix 32 bit wraparound in new ram detection drm/nouveau/secboot/gm20b: fix the error return code in gm20b_secboot_tegra_read_wpr() drm/nouveau/kms: Increase max retries in scanout position queries. drm/nouveau/bios/bitP: check that table is long enough for optional pointers drm/nouveau/fifo/nv40: no ctxsw for pre-nv44 mpeg engine drm: mali-dp: use div_u64 for expensive 64-bit divisions drm/i915: Confirm the request is still active before adding it to the await drm/i915: Avoid busy-spinning on VLV_GLTC_PW_STATUS mmio drm/i915/selftests: Allocate inode/file dynamically drm/i915: Fix system hang with EI UP masked on Haswell drm/i915: checking for NULL instead of IS_ERR() in mock selftests drm/i915: Perform link quality check unconditionally during long pulse drm/i915: Fix use after free in lpe_audio_platdev_destroy() drm/i915: Use the right mapping_gfp_mask for final shmem allocation drm/i915: Make legacy cursor updates more unsynced drm/i915: Apply a cond_resched() to the saturated signaler drm/i915: Park the signaler before sleeping drm: mali-dp: Check the mclk rate and allow up/down scaling drm: mali-dp: Enable image enhancement when scaling drm: mali-dp: Add plane upscaling support ...
2017-05-01Merge branch 'locking-core-for-linus' of ↵Linus Torvalds8-288/+418
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "The main changes in this cycle were: - a big round of FUTEX_UNLOCK_PI improvements, fixes, cleanups and general restructuring - lockdep updates such as new checks for lock_downgrade() - introduce the new atomic_try_cmpxchg() locking API and use it to optimize refcount code generation - ... plus misc fixes, updates and cleanups" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits) MAINTAINERS: Add FUTEX SUBSYSTEM futex: Clarify mark_wake_futex memory barrier usage futex: Fix small (and harmless looking) inconsistencies futex: Avoid freeing an active timer rtmutex: Plug preempt count leak in rt_mutex_futex_unlock() rtmutex: Fix more prio comparisons rtmutex: Fix PI chain order integrity sched,tracing: Update trace_sched_pi_setprio() sched/rtmutex: Refactor rt_mutex_setprio() rtmutex: Clean up sched/deadline/rtmutex: Dont miss the dl_runtime/dl_period update sched/rtmutex/deadline: Fix a PI crash for deadline tasks rtmutex: Deboost before waking up the top waiter locking/ww-mutex: Limit stress test to 2 seconds locking/atomic: Fix atomic_try_cmpxchg() semantics lockdep: Fix per-cpu static objects futex: Drop hb->lock before enqueueing on the rtmutex futex: Futex_unlock_pi() determinism futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock() futex,rt_mutex: Restructure rt_mutex_finish_proxy_lock() ...
2017-04-23Merge branch 'for-mingo' of ↵Ingo Molnar2-47/+48
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney: - Documentation updates. - Miscellaneous fixes. - Parallelize SRCU callback handling (plus overlapping patches). Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-19lockdep: Use "WARNING" tag on lockdep splatsPaul E. McKenney2-47/+48
This commit changes lockdep splats to begin lines with "WARNING" and to use pr_warn() instead of printk(). This change eases scripted analysis of kernel console output. Reported-by: Dmitry Vyukov <dvyukov@google.com> Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2017-04-18sparc64: Use LOCKDEP_SMALL, not PROVE_LOCKING_SMALLDaniel Jordan1-3/+3
CONFIG_PROVE_LOCKING_SMALL shrinks the memory usage of lockdep so the kernel text, data, and bss fit in the required 32MB limit, but this option is not set for every config that enables lockdep. A 4.10 kernel fails to boot with the console output Kernel: Using 8 locked TLB entries for main kernel image. hypervisor_tlb_lock[2000000:0:8000000071c007c3:1]: errors with f Program terminated with these config options CONFIG_LOCKDEP=y CONFIG_LOCK_STAT=y CONFIG_PROVE_LOCKING=n To fix, rename CONFIG_PROVE_LOCKING_SMALL to CONFIG_LOCKDEP_SMALL, and enable this option with CONFIG_LOCKDEP=y so we get the reduced memory usage every time lockdep is turned on. Tested that CONFIG_LOCKDEP_SMALL is set to 'y' if and only if CONFIG_LOCKDEP is set to 'y'. When other lockdep-related config options that select CONFIG_LOCKDEP are enabled (e.g. CONFIG_LOCK_STAT or CONFIG_PROVE_LOCKING), verified that CONFIG_LOCKDEP_SMALL is also enabled. Fixes: e6b5f1be7afe ("config: Adding the new config parameter CONFIG_PROVE_LOCKING_SMALL for sparc") Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Babu Moger <babu.moger@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-05rtmutex: Plug preempt count leak in rt_mutex_futex_unlock()Mike Galbraith1-5/+5
mark_wakeup_next_waiter() already disables preemption, doing so again leaves us with an unpaired preempt_disable(). Fixes: 2a1c60299406 ("rtmutex: Deboost before waking up the top waiter") Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Link: http://lkml.kernel.org/r/1491379707.6538.2.camel@gmx.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-04rtmutex: Fix more prio comparisonsPeter Zijlstra1-3/+29
There was a pure ->prio comparison left in try_to_wake_rt_mutex(), convert it to use rt_mutex_waiter_less(), noting that greater-or-equal is not-less (both in kernel priority view). This necessitated the introduction of cmp_task() which creates a pointer to an unnamed stack variable of struct rt_mutex_waiter type to compare against tasks. With this, we can now also create and employ rt_mutex_waiter_equal(). Reviewed-and-tested-by: Juri Lelli <juri.lelli@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170323150216.455584638@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-04rtmutex: Fix PI chain order integrityPeter Zijlstra2-2/+28
rt_mutex_waiter::prio is a copy of task_struct::prio which is updated during the PI chain walk, such that the PI chain order isn't messed up by (asynchronous) task state updates. Currently rt_mutex_waiter_less() uses task state for deadline tasks; this is broken, since the task state can, as said above, change asynchronously, causing the RB tree order to change without actual tree update -> FAIL. Fix this by also copying the deadline into the rt_mutex_waiter state and updating it along with its prio field. Ideally we would also force PI chain updates whenever DL tasks update their deadline parameter, but for first approximation this is less broken than it was. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170323150216.403992539@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-04sched/rtmutex: Refactor rt_mutex_setprio()Peter Zijlstra1-82/+30
With the introduction of SCHED_DEADLINE the whole notion that priority is a single number is gone, therefore the @prio argument to rt_mutex_setprio() doesn't make sense anymore. So rework the code to pass a pi_task instead. Note this also fixes a problem with pi_top_task caching; previously we would not set the pointer (call rt_mutex_update_top_task) if the priority didn't change, this could lead to a stale pointer. As for the XXX, I think its fine to use pi_task->prio, because if it differs from waiter->prio, a PI chain update is immenent. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170323150216.303827095@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-04rtmutex: Clean upPeter Zijlstra2-16/+14
Previous patches changed the meaning of the return value of rt_mutex_slowunlock(); update comments and code to reflect this. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170323150216.255058238@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-04sched/deadline/rtmutex: Dont miss the dl_runtime/dl_period updateXunlei Pang1-1/+1
Currently dl tasks will actually return at the very beginning of rt_mutex_adjust_prio_chain() in !detect_deadlock cases: if (waiter->prio == task->prio) { if (!detect_deadlock) goto out_unlock_pi; // out here else requeue = false; } As the deadline value of blocked deadline tasks(waiters) without changing their sched_class(thus prio doesn't change) never changes, this seems reasonable, but it actually misses the chance of updating rt_mutex_waiter's "dl_runtime(period)_copy" if a waiter updates its deadline parameters(dl_runtime, dl_period) or boosted waiter changes to !deadline class. Thus, force deadline task not out by adding the !dl_prio() condition. Signed-off-by: Xunlei Pang <xlpang@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/1460633827-345-7-git-send-email-xlpang@redhat.com Link: http://lkml.kernel.org/r/20170323150216.206577901@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-04sched/rtmutex/deadline: Fix a PI crash for deadline tasksXunlei Pang1-8/+21
A crash happened while I was playing with deadline PI rtmutex. BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 IP: [<ffffffff810eeb8f>] rt_mutex_get_top_task+0x1f/0x30 PGD 232a75067 PUD 230947067 PMD 0 Oops: 0000 [#1] SMP CPU: 1 PID: 10994 Comm: a.out Not tainted Call Trace: [<ffffffff810b658c>] enqueue_task+0x2c/0x80 [<ffffffff810ba763>] activate_task+0x23/0x30 [<ffffffff810d0ab5>] pull_dl_task+0x1d5/0x260 [<ffffffff810d0be6>] pre_schedule_dl+0x16/0x20 [<ffffffff8164e783>] __schedule+0xd3/0x900 [<ffffffff8164efd9>] schedule+0x29/0x70 [<ffffffff8165035b>] __rt_mutex_slowlock+0x4b/0xc0 [<ffffffff81650501>] rt_mutex_slowlock+0xd1/0x190 [<ffffffff810eeb33>] rt_mutex_timed_lock+0x53/0x60 [<ffffffff810ecbfc>] futex_lock_pi.isra.18+0x28c/0x390 [<ffffffff810ed8b0>] do_futex+0x190/0x5b0 [<ffffffff810edd50>] SyS_futex+0x80/0x180 This is because rt_mutex_enqueue_pi() and rt_mutex_dequeue_pi() are only protected by pi_lock when operating pi waiters, while rt_mutex_get_top_task(), will access them with rq lock held but not holding pi_lock. In order to tackle it, we introduce new "pi_top_task" pointer cached in task_struct, and add new rt_mutex_update_top_task() to update its value, it can be called by rt_mutex_setprio() which held both owner's pi_lock and rq lock. Thus "pi_top_task" can be safely accessed by enqueue_task_dl() under rq lock. Originally-From: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Xunlei Pang <xlpang@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170323150216.157682758@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-04rtmutex: Deboost before waking up the top waiterXunlei Pang2-28/+33
We should deboost before waking the high-priority task, such that we don't run two tasks with the same "state" (priority, deadline, sched_class, etc). In order to make sure the boosting task doesn't start running between unlock and deboost (due to 'spurious' wakeup), we move the deboost under the wait_lock, that way its serialized against the wait loop in __rt_mutex_slowlock(). Doing the deboost early can however lead to priority-inversion if current would get preempted after the deboost but before waking our high-prio task, hence we disable preemption before doing deboost, and enabling it after the wake up is over. This gets us the right semantic order, but most importantly however; this change ensures pointer stability for the next patch, where we have rt_mutex_setprio() cache a pointer to the top-most waiter task. If we, as before this change, do the wakeup first and then deboost, this pointer might point into thin air. [peterz: Changelog + patch munging] Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Xunlei Pang <xlpang@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170323150216.110065320@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-30locking/ww-mutex: Limit stress test to 2 secondsChris Wilson1-9/+9
Use a timeout rather than a fixed number of loops to avoid running for very long periods, such as under the kbuilder VMs. Reported-by: kernel test robot <xiaolong.ye@intel.com> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170310105733.6444-1-chris@chris-wilson.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-23futex: Drop hb->lock before enqueueing on the rtmutexPeter Zijlstra2-21/+31
When PREEMPT_RT_FULL does the spinlock -> rt_mutex substitution the PI chain code will (falsely) report a deadlock and BUG. The problem is that it hold hb->lock (now an rt_mutex) while doing task_blocks_on_rt_mutex on the futex's pi_state::rtmutex. This, when interleaved just right with futex_unlock_pi() leads it to believe to see an AB-BA deadlock. Task1 (holds rt_mutex, Task2 (does FUTEX_LOCK_PI) does FUTEX_UNLOCK_PI) lock hb->lock lock rt_mutex (as per start_proxy) lock hb->lock Which is a trivial AB-BA. It is not an actual deadlock, because it won't be holding hb->lock by the time it actually blocks on the rt_mutex, but the chainwalk code doesn't know that and it would be a nightmare to handle this gracefully. To avoid this problem, do the same as in futex_unlock_pi() and drop hb->lock after acquiring wait_lock. This still fully serializes against futex_unlock_pi(), since adding to the wait_list does the very same lock dance, and removing it holds both locks. Aside of solving the RT problem this makes the lock and unlock mechanism symetric and reduces the hb->lock held time. Reported-and-tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: juri.lelli@arm.com Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: dvhart@infradead.org Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170322104152.161341537@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-23futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()Peter Zijlstra2-20/+7
By changing futex_lock_pi() to use rt_mutex_*_proxy_lock() all wait_list modifications are done under both hb->lock and wait_lock. This closes the obvious interleave pattern between futex_lock_pi() and futex_unlock_pi(), but not entirely so. See below: Before: futex_lock_pi() futex_unlock_pi() unlock hb->lock lock hb->lock unlock hb->lock lock rt_mutex->wait_lock unlock rt_mutex_wait_lock -EAGAIN lock rt_mutex->wait_lock list_add unlock rt_mutex->wait_lock schedule() lock rt_mutex->wait_lock list_del unlock rt_mutex->wait_lock <idem> -EAGAIN lock hb->lock After: futex_lock_pi() futex_unlock_pi() lock hb->lock lock rt_mutex->wait_lock list_add unlock rt_mutex->wait_lock unlock hb->lock schedule() lock hb->lock unlock hb->lock lock hb->lock lock rt_mutex->wait_lock list_del unlock rt_mutex->wait_lock lock rt_mutex->wait_lock unlock rt_mutex_wait_lock -EAGAIN unlock hb->lock It does however solve the earlier starvation/live-lock scenario which got introduced with the -EAGAIN since unlike the before scenario; where the -EAGAIN happens while futex_unlock_pi() doesn't hold any locks; in the after scenario it happens while futex_unlock_pi() actually holds a lock, and then it is serialized on that lock. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: dvhart@infradead.org Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170322104152.062785528@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-23futex,rt_mutex: Restructure rt_mutex_finish_proxy_lock()Peter Zijlstra2-10/+50
With the ultimate goal of keeping rt_mutex wait_list and futex_q waiters consistent it's necessary to split 'rt_mutex_futex_lock()' into finer parts, such that only the actual blocking can be done without hb->lock held. Split split_mutex_finish_proxy_lock() into two parts, one that does the blocking and one that does remove_waiter() when the lock acquire failed. When the rtmutex was acquired successfully the waiter can be removed in the acquisiton path safely, since there is no concurrency on the lock owner. This means that, except for futex_lock_pi(), all wait_list modifications are done with both hb->lock and wait_lock held. [bigeasy@linutronix.de: fix for futex_requeue_pi_signal_restart] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: dvhart@infradead.org Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170322104152.001659630@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-23futex,rt_mutex: Introduce rt_mutex_init_waiter()Peter Zijlstra2-3/+10
Since there's already two copies of this code, introduce a helper now before adding a third one. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: dvhart@infradead.org Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170322104151.950039479@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-23futex,rt_mutex: Provide futex specific rt_mutex APIPeter Zijlstra2-16/+48
Part of what makes futex_unlock_pi() intricate is that rt_mutex_futex_unlock() -> rt_mutex_slowunlock() can drop rt_mutex::wait_lock. This means it cannot rely on the atomicy of wait_lock, which would be preferred in order to not rely on hb->lock so much. The reason rt_mutex_slowunlock() needs to drop wait_lock is because it can race with the rt_mutex fastpath, however futexes have their own fast path. Since futexes already have a bunch of separate rt_mutex accessors, complete that set and implement a rt_mutex variant without fastpath for them. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: dvhart@infradead.org Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170322104151.702962446@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-23futex: Remove rt_mutex_deadlock_account_*()Peter Zijlstra4-43/+18
These are unused and clutter up the code. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: dvhart@infradead.org Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170322104151.652692478@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-23BackMerge tag 'v4.11-rc3' into drm-nextDave Airlie3-10/+23
Linux 4.11-rc3 as requested by Daniel
2017-03-16locking/ww_mutex: Improve test to cover acquire context changesPeter Zijlstra1-8/+7
Currently each thread starts an acquire context only once, and performs all its loop iterations under it. This means that the Wound/Wait relations between threads are fixed. To make things a little more realistic and cover more of the functionality with the test, open a new acquire context for each loop. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-16locking/lockdep: Handle statically initialized PER_CPU locks properlyThomas Gleixner1-10/+23
If a PER_CPU struct which contains a spin_lock is statically initialized via: DEFINE_PER_CPU(struct foo, bla) = { .lock = __SPIN_LOCK_UNLOCKED(bla.lock) }; then lockdep assigns a seperate key to each lock because the logic for assigning a key to statically initialized locks is to use the address as the key. With per CPU locks the address is obvioulsy different on each CPU. That's wrong, because all locks should have the same key. To solve this the following modifications are required: 1) Extend the is_kernel/module_percpu_addr() functions to hand back the canonical address of the per CPU address, i.e. the per CPU address minus the per CPU offset. 2) Check the lock address with these functions and if the per CPU check matches use the returned canonical address as the lock key, so all per CPU locks have the same key. 3) Move the static_obj(key) check into look_up_lock_class() so this check can be avoided for statically initialized per CPU locks. That's required because the canonical address fails the static_obj(key) check for obvious reasons. Reported-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [ Merged Dan's fixups for !MODULES and !SMP into this patch. ] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dan Murphy <dmurphy@ti.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20170227143736.pectaimkjkan5kow@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-16locking/lockdep: Add new check to lock_downgrade()J. R. Okajima2-4/+57
Commit: f8319483f57f ("locking/lockdep: Provide a type check for lock_is_held") didn't fully cover rwsems as downgrade_write() was left out. Introduce lock_downgrade() and use it to add new checks. See-also: http://marc.info/?l=linux-kernel&m=148581164003149&w=2 Originally-written-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: J. R. Okajima <hooanon05g@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1486053497-9948-3-git-send-email-hooanon05g@gmail.com [ Rewrote the changelog. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-16locking/lockdep: Factor out the validate_held_lock() helper functionJ. R. Okajima1-18/+22
Behaviour should not change. Signed-off-by: J. R. Okajima <hooanon05g@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1486053497-9948-2-git-send-email-hooanon05g@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-16locking/lockdep: Factor out the find_held_lock() helper functionJ. R. Okajima1-60/+54
A simple consolidataion to factor out repeated patterns. The behaviour should not change. Signed-off-by: J. R. Okajima <hooanon05g@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1486053497-9948-1-git-send-email-hooanon05g@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-16locking/rwsem: Fix down_write_killable() for CONFIG_RWSEM_GENERIC_SPINLOCK=yNiklas Cassel1-5/+11
We hang if SIGKILL has been sent, but the task is stuck in down_read() (after do_exit()), even though no task is doing down_write() on the rwsem in question: INFO: task libupnp:21868 blocked for more than 120 seconds. libupnp D 0 21868 1 0x08100008 ... Call Trace: __schedule() schedule() __down_read() do_exit() do_group_exit() __wake_up_parent() This bug has already been fixed for CONFIG_RWSEM_XCHGADD_ALGORITHM=y in the following commit: 04cafed7fc19 ("locking/rwsem: Fix down_write_killable()") ... however, this bug also exists for CONFIG_RWSEM_GENERIC_SPINLOCK=y. Signed-off-by: Niklas Cassel <niklas.cassel@axis.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <mhocko@suse.com> Cc: <stable@vger.kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Niklas Cassel <niklass@axis.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: d47996082f52 ("locking/rwsem: Introduce basis for down_write_killable()") Link: http://lkml.kernel.org/r/1487981873-12649-1-git-send-email-niklass@axis.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-14drm/i915: annote drop_caches debugfs interface with lockdepDaniel Vetter1-0/+2
The trouble we have is that we can't really test all the shrinker recursion stuff exhaustively in BAT because any kind of thrashing stress test just takes too long. But that leaves a really big gap open, since shrinker recursions are one of the most annoying bugs. Now lockdep already has support for checking allocation deadlocks: - Direct reclaim paths are marked up with lockdep_set_current_reclaim_state() and lockdep_clear_current_reclaim_state(). - Any allocation paths are marked with lockdep_trace_alloc(). If we simply mark up our debugfs with the reclaim annotations, any code and locks taken in there will automatically complete the picture with any allocation paths we already have, as long as we have a simple testcase in BAT which throws out a few objects using this interface. Not stress test or thrashing needed at all. v2: Need to EXPORT_SYMBOL_GPL to make it compile as a module. v3: Fixup rebase fail (spotted by Chris). Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: linux-kernel@vger.kernel.org Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: http://patchwork.freedesktop.org/patch/msgid/20170312205340.16202-1-daniel.vetter@ffwll.ch Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2017-03-07Merge branch 'locking-urgent-for-linus' of ↵Linus Torvalds2-5/+12
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fixes from Ingo Molnar: - Change the new refcount_t warnings from WARN() to WARN_ONCE() - two ww_mutex fixes - plus a new lockdep self-consistency check for a bug that triggered in practice * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/ww_mutex: Adjust the lock number for stress test locking/lockdep: Add nest_lock integrity test locking/ww_mutex: Replace cpu_relax() with cond_resched() for tests locking/refcounts: Change WARN() to WARN_ONCE()
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-11 14:52:12 +0000