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2023-04-20net: extend drop reasons for multiple subsystemsJohannes Berg1-9/+24
Extend drop reasons to make them usable by subsystems other than core by reserving the high 16 bits for a new subsystem ID, of which 0 of course is used for the existing reasons immediately. To still be able to have string reasons, restructure that code a bit to make the loopup under RCU, the only user of this (right now) is drop_monitor. Link: https://lore.kernel.org/netdev/00659771ed54353f92027702c5bbb84702da62ce.camel@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-07genetlink: introduce split op representationJakub Kicinski1-2/+2
We currently have two forms of operations - small ops and "full" ops (or just ops). The former does not have pointers for some of the less commonly used features (namely dump start/done and policy). The "full" ops, however, still don't contain all the necessary information. In particular the policy is per command ID, while do and dump often accept different attributes. It's also not possible to define different pre_doit and post_doit callbacks for different commands within the family. At the same time a lot of commands do not support dumping and therefore all the dump-related information is wasted space. Create a new command representation which can hold info about a do implementation or a dump implementation, but not both at the same time. Use this new representation on the command execution path (genl_family_rcv_msg) as we either run a do or a dump and don't have to create a "full" op there. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-10-28net: Remove the obsolte u64_stats_fetch_*_irq() users (net).Thomas Gleixner1-4/+4
Now that the 32bit UP oddity is gone and 32bit uses always a sequence count, there is no need for the fetch_irq() variants anymore. Convert to the regular interface. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-29genetlink: start to validate reserved header bytesJakub Kicinski1-0/+1
We had historically not checked that genlmsghdr.reserved is 0 on input which prevents us from using those precious bytes in the future. One use case would be to extend the cmd field, which is currently just 8 bits wide and 256 is not a lot of commands for some core families. To make sure that new families do the right thing by default put the onus of opting out of validation on existing families. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> (NetLabel) Signed-off-by: David S. Miller <davem@davemloft.net>
2022-08-22net: move from strlcpy with unused retval to strscpyWolfram Sang1-1/+1
Follow the advice of the below link and prefer 'strscpy' in this subsystem. Conversion is 1:1 because the return value is not used. Generated by a coccinelle script. Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/ Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Link: https://lore.kernel.org/r/20220818210215.8395-1-wsa+renesas@sang-engineering.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-09drop_monitor: adopt u64_stats_tEric Dumazet1-9/+9
As explained in commit 316580b69d0a ("u64_stats: provide u64_stats_t type") we should use u64_stats_t and related accessors to avoid load/store tearing. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-09net: rename reference+tracking helpersJakub Kicinski1-2/+3
Netdev reference helpers have a dev_ prefix for historic reasons. Renaming the old helpers would be too much churn but we can rename the tracking ones which are relatively recent and should be the default for new code. Rename: dev_hold_track() -> netdev_hold() dev_put_track() -> netdev_put() dev_replace_track() -> netdev_ref_replace() Link: https://lore.kernel.org/r/20220608043955.919359-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-07net: skb: use auto-generation to convert skb drop reason to stringMenglong Dong1-13/+0
It is annoying to add new skb drop reasons to 'enum skb_drop_reason' and TRACE_SKB_DROP_REASON in trace/event/skb.h, and it's easy to forget to add the new reasons we added to TRACE_SKB_DROP_REASON. TRACE_SKB_DROP_REASON is used to convert drop reason of type number to string. For now, the string we passed to user space is exactly the same as the name in 'enum skb_drop_reason' with a 'SKB_DROP_REASON_' prefix. Therefore, we can use 'auto-generation' to generate these drop reasons to string at build time. The new source 'dropreason_str.c' will be auto generated during build time, which contains the string array 'const char * const drop_reasons[]'. Signed-off-by: Menglong Dong <imagedong@tencent.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-05-16net: dm: check the boundary of skb drop reasonsMenglong Dong1-1/+1
The 'reason' will be set to 'SKB_DROP_REASON_NOT_SPECIFIED' if it not small that SKB_DROP_REASON_MAX in net_dm_packet_trace_kfree_skb_hit(), but it can't avoid it to be 0, which is invalid and can cause NULL pointer in drop_reasons. Therefore, reset it to SKB_DROP_REASON_NOT_SPECIFIED when 'reason <= 0'. Reviewed-by: Jiang Biao <benbjiang@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Menglong Dong <imagedong@tencent.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-23drop_monitor: remove quadratic behaviorEric Dumazet1-55/+24
drop_monitor is using an unique list on which all netdevices in the host have an element, regardless of their netns. This scales poorly, not only at device unregister time (what I caught during my netns dismantle stress tests), but also at packet processing time whenever trace_napi_poll_hit() is called. If the intent was to avoid adding one pointer in 'struct net_device' then surely we prefer O(1) behavior. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-2/+9
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-11drop_monitor: fix data-race in dropmon_net_event / trace_napi_poll_hitEric Dumazet1-2/+9
trace_napi_poll_hit() is reading stat->dev while another thread can write on it from dropmon_net_event() Use READ_ONCE()/WRITE_ONCE() here, RCU rules are properly enforced already, we only have to take care of load/store tearing. BUG: KCSAN: data-race in dropmon_net_event / trace_napi_poll_hit write to 0xffff88816f3ab9c0 of 8 bytes by task 20260 on cpu 1: dropmon_net_event+0xb8/0x2b0 net/core/drop_monitor.c:1579 notifier_call_chain kernel/notifier.c:84 [inline] raw_notifier_call_chain+0x53/0xb0 kernel/notifier.c:392 call_netdevice_notifiers_info net/core/dev.c:1919 [inline] call_netdevice_notifiers_extack net/core/dev.c:1931 [inline] call_netdevice_notifiers net/core/dev.c:1945 [inline] unregister_netdevice_many+0x867/0xfb0 net/core/dev.c:10415 ip_tunnel_delete_nets+0x24a/0x280 net/ipv4/ip_tunnel.c:1123 vti_exit_batch_net+0x2a/0x30 net/ipv4/ip_vti.c:515 ops_exit_list net/core/net_namespace.c:173 [inline] cleanup_net+0x4dc/0x8d0 net/core/net_namespace.c:597 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307 worker_thread+0x616/0xa70 kernel/workqueue.c:2454 kthread+0x1bf/0x1e0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 read to 0xffff88816f3ab9c0 of 8 bytes by interrupt on cpu 0: trace_napi_poll_hit+0x89/0x1c0 net/core/drop_monitor.c:292 trace_napi_poll include/trace/events/napi.h:14 [inline] __napi_poll+0x36b/0x3f0 net/core/dev.c:6366 napi_poll net/core/dev.c:6432 [inline] net_rx_action+0x29e/0x650 net/core/dev.c:6519 __do_softirq+0x158/0x2de kernel/softirq.c:558 do_softirq+0xb1/0xf0 kernel/softirq.c:459 __local_bh_enable_ip+0x68/0x70 kernel/softirq.c:383 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline] _raw_spin_unlock_bh+0x33/0x40 kernel/locking/spinlock.c:210 spin_unlock_bh include/linux/spinlock.h:394 [inline] ptr_ring_consume_bh include/linux/ptr_ring.h:367 [inline] wg_packet_decrypt_worker+0x73c/0x780 drivers/net/wireguard/receive.c:506 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307 worker_thread+0x616/0xa70 kernel/workqueue.c:2454 kthread+0x1bf/0x1e0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 value changed: 0xffff88815883e000 -> 0x0000000000000000 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 26435 Comm: kworker/0:1 Not tainted 5.17.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: wg-crypt-wg2 wg_packet_decrypt_worker Fixes: 4ea7e38696c7 ("dropmon: add ability to detect when hardware dropsrxpackets") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neil Horman <nhorman@tuxdriver.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-09net: drop_monitor: support drop reasonMenglong Dong1-6/+35
In the commit c504e5c2f964 ("net: skb: introduce kfree_skb_reason()") drop reason is introduced to the tracepoint of kfree_skb. Therefore, drop_monitor is able to report the drop reason to users by netlink. The drop reasons are reported as string to users, which is exactly the same as what we do when reporting it to ftrace. Signed-off-by: Menglong Dong <imagedong@tencent.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20220209060838.55513-1-imagedong@tencent.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-01-09net: skb: introduce kfree_skb_reason()Menglong Dong1-3/+7
Introduce the interface kfree_skb_reason(), which is able to pass the reason why the skb is dropped to 'kfree_skb' tracepoint. Add the 'reason' field to 'trace_kfree_skb', therefor user can get more detail information about abnormal skb with 'drop_monitor' or eBPF. All drop reasons are defined in the enum 'skb_drop_reason', and they will be print as string in 'kfree_skb' tracepoint in format of 'reason: XXX'. ( Maybe the reasons should be defined in a uapi header file, so that user space can use them? ) Signed-off-by: Menglong Dong <imagedong@tencent.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-06drop_monitor: add net device refcount trackerEric Dumazet1-3/+3
We want to track all dev_hold()/dev_put() to ease leak hunting. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-05net: Remove redundant if statementsYajun Deng1-4/+2
The 'if (dev)' statement already move into dev_{put , hold}, so remove redundant if statements. Signed-off-by: Yajun Deng <yajun.deng@linux.dev> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-25Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-0/+23
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-18/net/core/: fix misspellings using codespell toolXiong Zhenwu1-1/+1
A typo is found out by codespell tool in 1734th line of drop_monitor.c: $ codespell ./net/core/ ./net/core/drop_monitor.c:1734: guarnateed ==> guaranteed Fix a typo found by codespell. Signed-off-by: Xiong Zhenwu <xiong.zhenwu@zte.com.cn> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-10drop_monitor: Perform cleanup upon probe registration failureIdo Schimmel1-0/+23
In the rare case that drop_monitor fails to register its probe on the 'napi_poll' tracepoint, it will not deactivate its hysteresis timer as part of the error path. If the hysteresis timer was armed by the shortly lived 'kfree_skb' probe and user space retries to initiate tracing, a warning will be emitted for trying to initialize an active object [1]. Fix this by properly undoing all the operations that were done prior to probe registration, in both software and hardware code paths. Note that syzkaller managed to fail probe registration by injecting a slab allocation failure [2]. [1] ODEBUG: init active (active state 0) object type: timer_list hint: sched_send_work+0x0/0x60 include/linux/list.h:135 WARNING: CPU: 1 PID: 8649 at lib/debugobjects.c:505 debug_print_object+0x16e/0x250 lib/debugobjects.c:505 Modules linked in: CPU: 1 PID: 8649 Comm: syz-executor.0 Not tainted 5.11.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:debug_print_object+0x16e/0x250 lib/debugobjects.c:505 [...] Call Trace: __debug_object_init+0x524/0xd10 lib/debugobjects.c:588 debug_timer_init kernel/time/timer.c:722 [inline] debug_init kernel/time/timer.c:770 [inline] init_timer_key+0x2d/0x340 kernel/time/timer.c:814 net_dm_trace_on_set net/core/drop_monitor.c:1111 [inline] set_all_monitor_traces net/core/drop_monitor.c:1188 [inline] net_dm_monitor_start net/core/drop_monitor.c:1295 [inline] net_dm_cmd_trace+0x720/0x1220 net/core/drop_monitor.c:1339 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739 genl_family_rcv_msg net/netlink/genetlink.c:783 [inline] genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:800 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2502 genl_rcv+0x24/0x40 net/netlink/genetlink.c:811 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2348 ___sys_sendmsg+0xf3/0x170 net/socket.c:2402 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2435 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae [2] FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 1 CPU: 1 PID: 8645 Comm: syz-executor.0 Not tainted 5.11.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: dump_stack+0xfa/0x151 should_fail.cold+0x5/0xa should_failslab+0x5/0x10 __kmalloc+0x72/0x3f0 tracepoint_add_func+0x378/0x990 tracepoint_probe_register+0x9c/0xe0 net_dm_cmd_trace+0x7fc/0x1220 genl_family_rcv_msg_doit+0x228/0x320 genl_rcv_msg+0x328/0x580 netlink_rcv_skb+0x153/0x420 genl_rcv+0x24/0x40 netlink_unicast+0x533/0x7d0 netlink_sendmsg+0x856/0xd90 sock_sendmsg+0xcf/0x120 ____sys_sendmsg+0x6e8/0x810 ___sys_sendmsg+0xf3/0x170 __sys_sendmsg+0xe5/0x1b0 do_syscall_64+0x2d/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: 70c69274f354 ("drop_monitor: Initialize timer and work item upon tracing enable") Fixes: 8ee2267ad33e ("drop_monitor: Convert to using devlink tracepoint") Reported-by: syzbot+779559d6503f3a56213d@syzkaller.appspotmail.com Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: Jiri Pirko <jiri@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-10-02genetlink: move to smaller ops wherever possibleJakub Kicinski1-3/+3
Bulk of the genetlink users can use smaller ops, move them. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30drop_monitor: Filter control packets in drop monitorIdo Schimmel1-0/+6
Previously, devlink called into drop monitor in order to report hardware originated drops / exceptions. devlink intentionally filtered control packets and did not pass them to drop monitor as they were not dropped by the underlying hardware. Now drop monitor registers its probe on a generic 'devlink_trap_report' tracepoint and should therefore perform this filtering itself instead of having devlink do that. Add the trap type as metadata and have drop monitor ignore control packets. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30drop_monitor: Remove duplicate structIdo Schimmel1-17/+10
'struct net_dm_hw_metadata' is a duplicate of 'struct devlink_trap_metadata'. Remove the former and simplify the code. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30drop_monitor: Remove no longer used functionsIdo Schimmel1-142/+0
The old probe functions that were invoked by drop monitor code are no longer called and can thus be removed. They were replaced by actual probe functions that are registered on the recently introduced 'devlink_trap_report' tracepoint. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30drop_monitor: Convert to using devlink tracepointIdo Schimmel1-16/+40
Convert drop monitor to use the recently introduced 'devlink_trap_report' tracepoint instead of having devlink call into drop monitor. This is both consistent with software originated drops ('kfree_skb' tracepoint) and also allows drop monitor to be built as a module and still report hardware originated drops. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30drop_monitor: Prepare probe functions for devlink tracepointIdo Schimmel1-0/+146
Drop monitor supports two alerting modes: Summary and packet. Prepare a probe function for each, so that they could be later registered on the devlink tracepoint by calling register_trace_devlink_trap_report(), based on the configured alerting mode. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-23treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva1-1/+1
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-06-20net: Add MODULE_DESCRIPTION entries to network modulesRob Gill1-0/+1
The user tool modinfo is used to get information on kernel modules, including a description where it is available. This patch adds a brief MODULE_DESCRIPTION to the following modules: 9p drop_monitor esp4_offload esp6_offload fou fou6 ila sch_fq sch_fq_codel sch_hhf Signed-off-by: Rob Gill <rrobgill@protonmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-01drop_monitor: work around gcc-10 stringop-overflow warningArnd Bergmann1-4/+7
The current gcc-10 snapshot produces a false-positive warning: net/core/drop_monitor.c: In function 'trace_drop_common.constprop': cc1: error: writing 8 bytes into a region of size 0 [-Werror=stringop-overflow=] In file included from net/core/drop_monitor.c:23: include/uapi/linux/net_dropmon.h:36:8: note: at offset 0 to object 'entries' with size 4 declared here 36 | __u32 entries; | ^~~~~~~ I reported this in the gcc bugzilla, but in case it does not get fixed in the release, work around it by using a temporary variable. Fixes: 9a8afc8d3962 ("Network Drop Monitor: Adding drop monitor implementation & Netlink protocol") Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94881 Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-28net: core: Replace zero-length array with flexible-array memberGustavo A. R. Silva1-1/+1
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-25drop_monitor: extend by passing cookie from driverJiri Pirko1-1/+32
If driver passed along the cookie, push it through Netlink. Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-07drop_monitor: Do not cancel uninitialized work itemIdo Schimmel1-1/+3
Drop monitor uses a work item that takes care of constructing and sending netlink notifications to user space. In case drop monitor never started to monitor, then the work item is uninitialized and not associated with a function. Therefore, a stop command from user space results in canceling an uninitialized work item which leads to the following warning [1]. Fix this by not processing a stop command if drop monitor is not currently monitoring. [1] [ 31.735402] ------------[ cut here ]------------ [ 31.736470] WARNING: CPU: 0 PID: 143 at kernel/workqueue.c:3032 __flush_work+0x89f/0x9f0 ... [ 31.738120] CPU: 0 PID: 143 Comm: dwdump Not tainted 5.5.0-custom-09491-g16d4077796b8 #727 [ 31.741968] RIP: 0010:__flush_work+0x89f/0x9f0 ... [ 31.760526] Call Trace: [ 31.771689] __cancel_work_timer+0x2a6/0x3b0 [ 31.776809] net_dm_cmd_trace+0x300/0xef0 [ 31.777549] genl_rcv_msg+0x5c6/0xd50 [ 31.781005] netlink_rcv_skb+0x13b/0x3a0 [ 31.784114] genl_rcv+0x29/0x40 [ 31.784720] netlink_unicast+0x49f/0x6a0 [ 31.787148] netlink_sendmsg+0x7cf/0xc80 [ 31.790426] ____sys_sendmsg+0x620/0x770 [ 31.793458] ___sys_sendmsg+0xfd/0x170 [ 31.802216] __sys_sendmsg+0xdf/0x1a0 [ 31.806195] do_syscall_64+0xa0/0x540 [ 31.806885] entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: 8e94c3bc922e ("drop_monitor: Allow user to start monitoring hardware drops") Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-30net: drop_monitor: Use kstrdupJoe Perches1-6/+2
Convert the equivalent but rather odd uses of kmemdup with __GFP_ZERO to the more common kstrdup and avoid unnecessary zeroing of copied over memory. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-09-16drop_monitor: Better sanitize notified packetsIdo Schimmel1-0/+6
When working in 'packet' mode, drop monitor generates a notification with a potentially truncated payload of the dropped packet. The payload is copied from the MAC header, but I forgot to check that the MAC header was set, so do it now. Fixes: ca30707dee2b ("drop_monitor: Add packet alert mode") Fixes: 5e58109b1ea4 ("drop_monitor: Add support for packet alert mode for hardware drops") Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-23drop_monitor: Make timestamps y2038 safeIdo Schimmel1-8/+6
Timestamps are currently communicated to user space as 'struct timespec', which is not considered y2038 safe since it uses a 32-bit signed value for seconds. Fix this while the API is still not part of any official kernel release by using 64-bit nanoseconds timestamps instead. Fixes: ca30707dee2b ("drop_monitor: Add packet alert mode") Fixes: 5e58109b1ea4 ("drop_monitor: Add support for packet alert mode for hardware drops") Signed-off-by: Ido Schimmel <idosch@mellanox.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17drop_monitor: Allow user to start monitoring hardware dropsIdo Schimmel1-3/+121
Drop monitor has start and stop commands, but so far these were only used to start and stop monitoring of software drops. Now that drop monitor can also monitor hardware drops, we should allow the user to control these as well. Do that by adding SW and HW flags to these commands. If no flag is specified, then only start / stop monitoring software drops. This is done in order to maintain backward-compatibility with existing user space applications. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17drop_monitor: Add support for summary alert mode for hardware dropsIdo Schimmel1-2/+193
In summary alert mode a notification is sent with a list of recent drop reasons and a count of how many packets were dropped due to this reason. To avoid expensive operations in the context in which packets are dropped, each CPU holds an array whose number of entries is the maximum number of drop reasons that can be encoded in the netlink notification. Each entry stores the drop reason and a count. When a packet is dropped the array is traversed and a new entry is created or the count of an existing entry is incremented. Later, in process context, the array is replaced with a newly allocated copy and the old array is encoded in a netlink notification. To avoid breaking user space, the notification includes the ancillary header, which is 'struct net_dm_alert_msg' with number of entries set to '0'. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17drop_monitor: Add support for packet alert mode for hardware dropsIdo Schimmel1-4/+300
In a similar fashion to software drops, extend drop monitor to send netlink events when packets are dropped by the underlying hardware. The main difference is that instead of encoding the program counter (PC) from which kfree_skb() was called in the netlink message, we encode the hardware trap name. The two are mostly equivalent since they should both help the user understand why the packet was dropped. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17drop_monitor: Consider all monitoring states before performing configurationIdo Schimmel1-2/+7
The drop monitor configuration (e.g., alert mode) is global, but user will be able to enable monitoring of only software or hardware drops. Therefore, ensure that monitoring of both software and hardware drops are disabled before allowing drop monitor configuration to take place. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17drop_monitor: Add basic infrastructure for hardware dropsIdo Schimmel1-0/+28
Export a function that can be invoked in order to report packets that were dropped by the underlying hardware along with metadata. Subsequent patches will add support for the different alert modes. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17drop_monitor: Initialize hardware per-CPU dataIdo Schimmel1-2/+23
Like software drops, hardware drops also need the same type of per-CPU data. Therefore, initialize it during module initialization and de-initialize it during module exit. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17drop_monitor: Move per-CPU data init/fini to separate functionsIdo Schimmel1-17/+36
Currently drop monitor only reports software drops to user space, but subsequent patches are going to add support for hardware drops. Like software drops, the per-CPU data of hardware drops needs to be initialized and de-initialized upon module initialization and exit. To avoid code duplication, break this code into separate functions, so that these could be re-used for hardware drops. No functional changes intended. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11drop_monitor: Expose tail drop counterIdo Schimmel1-0/+101
Previous patch made the length of the per-CPU skb drop list configurable. Expose a counter that shows how many packets could not be enqueued to this list. This allows users determine the desired queue length. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11drop_monitor: Make drop queue length configurableIdo Schimmel1-3/+16
In packet alert mode, each CPU holds a list of dropped skbs that need to be processed in process context and sent to user space. To avoid exhausting the system's memory the maximum length of this queue is currently set to 1000. Allow users to tune the length of this queue according to their needs. The configured length is reported to user space when drop monitor configuration is queried. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11drop_monitor: Add a command to query current configurationIdo Schimmel1-0/+48
Users should be able to query the current configuration of drop monitor before they start using it. Add a command to query the existing configuration which currently consists of alert mode and packet truncation length. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11drop_monitor: Allow truncation of dropped packetsIdo Schimmel1-0/+19
When sending dropped packets to user space it is not always necessary to copy the entire packet as usually only the headers are of interest. Allow user to specify the truncation length and add the original length of the packet as additional metadata to the netlink message. By default no truncation is performed. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11drop_monitor: Add packet alert modeIdo Schimmel1-2/+278
So far drop monitor supported only one alert mode in which a summary of locations in which packets were recently dropped was sent to user space. This alert mode is sufficient in order to understand that packets were dropped, but lacks information to perform a more detailed analysis. Add a new alert mode in which the dropped packet itself is passed to user space along with metadata: The drop location (as program counter and resolved symbol), ingress netdevice and drop timestamp. More metadata can be added in the future. To avoid performing expensive operations in the context in which kfree_skb() is invoked (can be hard IRQ), the dropped skb is cloned and queued on per-CPU skb drop list. Then, in process context the netlink message is allocated, prepared and finally sent to user space. The per-CPU skb drop list is limited to 1000 skbs to prevent exhausting the system's memory. Subsequent patches will make this limit configurable and also add a counter that indicates how many skbs were tail dropped. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11drop_monitor: Add alert mode operationsIdo Schimmel1-6/+32
The next patch is going to add another alert mode in which the dropped packet is notified to user space, instead of only a summary of recent drops. Abstract the differences between the modes by adding alert mode operations. The operations are selected based on the currently configured mode and associated with the probes and the work item just before tracing starts. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11drop_monitor: Require CAP_NET_ADMIN for drop monitor configurationIdo Schimmel1-0/+1
Currently, the configure command does not do anything but return an error. Subsequent patches will enable the command to change various configuration options such as alert mode and packet truncation. Similar to other netlink-based configuration channels, make sure only users with the CAP_NET_ADMIN capability set can execute this command. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11drop_monitor: Reset per-CPU data before starting to traceIdo Schimmel1-3/+7
The function reset_per_cpu_data() allocates and prepares a new skb for the summary netlink alert message ('NET_DM_CMD_ALERT'). The new skb is stored in the per-CPU 'data' variable and the old is returned. The function is invoked during module initialization and from the workqueue, before an alert is sent. This means that it is possible to receive an alert with stale data, if we stopped tracing when the hysteresis timer ('data->send_timer') was pending. Instead of invoking the function during module initialization, invoke it just before we start tracing and ensure we get a fresh skb. This also allows us to remove the calls to initialize the timer and the work item from the module initialization path, since both could have been triggered by the error paths of reset_per_cpu_data(). Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11drop_monitor: Initialize timer and work item upon tracing enableIdo Schimmel1-5/+19
The timer and work item are currently initialized once during module init, but subsequent patches will need to associate different functions with the work item, based on the configured alert mode. Allow subsequent patches to make that change by initializing and de-initializing these objects during tracing enable and disable. This also guarantees that once the request to disable tracing returns, no more netlink notifications will be generated. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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