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authorThomas Petazzoni <thomas.petazzoni@free-electrons.com>2014-05-14 13:36:36 +0200
committerGrant Likely <grant.likely@linaro.org>2014-05-14 15:27:36 +0100
commit582da6527da30f6e21a95c9f3f2810d46a8f406e (patch)
tree741635e721d5a430d5ac41ab9a8fd80122296359 /drivers/of/base.c
parent14186fea0cb06bc43181ce239efe0df6f1af260a (diff)
of: make of_update_property() usable earlier in the boot process
Commit 75b57ecf9d1d1e17d099ab13b8f48e6e038676be ('of: Make device nodes kobjects so they show up in sysfs') has turned Device Tree nodes in kobjects and added a sysfs based representation for Device Tree nodes. Since the sysfs logic is only available after the execution of a core_initcall(), the patch took precautions in of_add_property() and of_remove_property() to not do any sysfs related manipulation early in the boot process. However, it forgot to do the same for of_update_property(), which if used early in the boot process (before core_initcalls have been called), tries to call sysfs_remove_bin_file(), and crashes: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at /home/thomas/projets/linux-2.6/fs/kernfs/dir.c:1216 kernfs_remove_by_name_ns+0x80/0x88() kernfs: can not remove '(null)', no directory Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.15.0-rc1-00127-g1d7e7b2-dirty #423 [<c0014910>] (unwind_backtrace) from [<c00110ec>] (show_stack+0x10/0x14) [<c00110ec>] (show_stack) from [<c04c84b8>] (dump_stack+0x84/0x94) [<c04c84b8>] (dump_stack) from [<c001d8c0>] (warn_slowpath_common+0x6c/0x88) [<c001d8c0>] (warn_slowpath_common) from [<c001d90c>] (warn_slowpath_fmt+0x30/0x40) [<c001d90c>] (warn_slowpath_fmt) from [<c0104468>] (kernfs_remove_by_name_ns+0x80/0x88) [<c0104468>] (kernfs_remove_by_name_ns) from [<c0394d98>] (of_update_property+0xc0/0xf0) [<c0394d98>] (of_update_property) from [<c0647248>] (mvebu_timer_and_clk_init+0xfc/0x194) [<c0647248>] (mvebu_timer_and_clk_init) from [<c0640934>] (start_kernel+0x218/0x350) [<c0640934>] (start_kernel) from [<00008070>] (0x8070) ---[ end trace 3406ff24bd97382e ]--- Unable to handle kernel NULL pointer dereference at virtual address 0000003c pgd = c0004000 [0000003c] *pgd=00000000 Internal error: Oops: 5 [#1] SMP ARM Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 3.15.0-rc1-00127-g1d7e7b2-dirty #423 task: c10ad4d8 ti: c10a2000 task.ti: c10a2000 PC is at kernfs_find_ns+0x8/0xf0 LR is at kernfs_find_and_get_ns+0x30/0x48 pc : [<c0103834>] lr : [<c010394c>] psr: 600001d3 sp : c10a3f34 ip : 00000073 fp : 00000000 r10: 00000000 r9 : cfffc240 r8 : cfdf2980 r7 : cf812c00 r6 : 00000000 r5 : 00000000 r4 : c10b45e0 r3 : c10ad4d8 r2 : 00000000 r1 : cf812c00 r0 : 00000000 Flags: nZCv IRQs off FIQs off Mode SVC_32 ISA ARM Segment kernel Control: 10c53c7d Table: 0000404a DAC: 00000015 Process swapper/0 (pid: 0, stack limit = 0xc10a2240) Stack: (0xc10a3f34 to 0xc10a4000) 3f20: c10b45e0 00000000 00000000 3f40: cf812c00 c010394c 00000063 cf812c00 00000001 cf812c00 cfdf29ac c03932cc 3f60: 00000063 cf812bc0 cfdf29ac cf812c00 ffffffff c03943f8 cfdf2980 c0104468 3f80: cfdf2a04 cfdf2980 cf812bc0 c06634b0 c10aa3c0 c0394da4 c10f74dc cfdf2980 3fa0: cf812bc0 c0647248 c10aa3c0 ffffffff c10de940 c10aa3c0 ffffffff c0640934 3fc0: ffffffff ffffffff c06404ec 00000000 00000000 c06634b0 00000000 10c53c7d 3fe0: c10aa434 c06634ac c10ae4c8 0000406a 414fc091 00008070 00000000 00000000 [<c0103834>] (kernfs_find_ns) from [<00000001>] (0x1) Code: e5c89001 eaffffcf e92d40f0 e1a06002 (e1d023bc) ---[ end trace 3406ff24bd97382f ]--- Kernel panic - not syncing: Attempted to kill the idle task! ---[ end Kernel panic - not syncing: Attempted to kill the idle task! To fix this problem, we simply skip the sysfs related calls in of_update_property(), and rely on of_init() to fix up things when it will be called, exactly as is done in of_add_property() and of_remove_property(). Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Fixes: 75b57ecf9d1d ("of: Make device nodes kobjects so they show up in sysfs") Signed-off-by: Grant Likely <grant.likely@linaro.org>
Diffstat (limited to 'drivers/of/base.c')
-rw-r--r--drivers/of/base.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 6d4ee22708c9..32e969d95319 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1831,6 +1831,10 @@ int of_update_property(struct device_node *np, struct property *newprop)
if (!found)
return -ENODEV;
+ /* At early boot, bail out and defer setup to of_init() */
+ if (!of_kset)
+ return found ? 0 : -ENODEV;
+
/* Update the sysfs attribute */
sysfs_remove_bin_file(&np->kobj, &oldprop->attr);
__of_add_property_sysfs(np, newprop);