From: Li Zhong Date: Mon, 22 Oct 2012 23:46:27 +0000 (+0000) Subject: powerpc: Fix MAX_STACK_TRACE_ENTRIES too low warning ! X-Git-Tag: v3.8-rc1~68^2~41 X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=12660b170253255c012cb1352449e61ae9727079;p=uclinux-h8%2Flinux.git powerpc: Fix MAX_STACK_TRACE_ENTRIES too low warning ! This patch tries to fix the following BUG report: [ 0.012313] BUG: MAX_STACK_TRACE_ENTRIES too low! [ 0.012318] turning off the locking correctness validator. [ 0.012321] Call Trace: [ 0.012330] [c00000017666f6d0] [c000000000012128] .show_stack+0x78/0x184 (unreliable) [ 0.012339] [c00000017666f780] [c0000000000b6348] .save_trace+0x12c/0x14c [ 0.012345] [c00000017666f800] [c0000000000b7448] .mark_lock+0x2bc/0x710 [ 0.012351] [c00000017666f8b0] [c0000000000bb198] .__lock_acquire+0x748/0xaec [ 0.012357] [c00000017666f9b0] [c0000000000bb684] .lock_acquire+0x148/0x194 [ 0.012365] [c00000017666fa80] [c00000000069371c] .mutex_lock_nested+0x84/0x4ec [ 0.012372] [c00000017666fb90] [c000000000096998] .smpboot_register_percpu_thread+0x3c/0x10c [ 0.012380] [c00000017666fc30] [c0000000009ba910] .spawn_ksoftirqd+0x28/0x48 [ 0.012386] [c00000017666fcb0] [c00000000000a98c] .do_one_initcall+0xd8/0x1d0 [ 0.012392] [c00000017666fd60] [c00000000000b1f8] .kernel_init+0x120/0x398 [ 0.012398] [c00000017666fe30] [c000000000009ad4] .ret_from_kernel_thread+0x5c/0x64 [ 0.012404] [c00000017666fa00] [c00000017666fb20] 0xc00000017666fb20 [ 0.012410] [c00000017666fa80] [c00000000069371c] .mutex_lock_nested+0x84/0x4ec [ 0.012416] [c00000017666fb90] [c000000000096998] .smpboot_register_percpu_thread+0x3c/0x10c [ 0.012422] [c00000017666fc30] [c0000000009ba910] .spawn_ksoftirqd+0x28/0x48 [ 0.012427] [c00000017666fcb0] [c00000000000a98c] .do_one_initcall+0xd8/0x1d0 [ 0.012433] [c00000017666fd60] [c00000000000b1f8] .kernel_init+0x120/0x398 [ 0.012439] [c00000017666fe30] [c000000000009ad4] .ret_from_kernel_thread+0x5c/0x64 ....... The reason is that the back chain of c00000017666fe30 (ret_from_kernel_thread) contains some invalid value, which might form a loop. Signed-off-by: Li Zhong Signed-off-by: Benjamin Herrenschmidt --- diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 56e0ff0878b5..ad7666695761 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -374,6 +374,8 @@ _GLOBAL(ret_from_kernel_thread) bl .schedule_tail REST_NVGPRS(r1) REST_GPR(2,r1) + li r3,0 + std r3,0(r1) mtlr r14 mr r3,r15 blrl