diff options
| author | Li Bin <huawei.libin@huawei.com> | 2015-09-30 10:49:55 +0800 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2015-10-02 11:12:56 +0100 |
| commit | ee556d00cf20012e889344a0adbbf809ab5015a3 (patch) | |
| tree | 21880eb6317793473dea4af2612e292479918f02 | |
| parent | 1a541b4e3cd6f5795022514114854b3e1345f24e (diff) | |
arm64: ftrace: fix function_graph tracer panic
When function graph tracer is enabled, the following operation
will trigger panic:
mount -t debugfs nodev /sys/kernel
echo next_tgid > /sys/kernel/tracing/set_ftrace_filter
echo function_graph > /sys/kernel/tracing/current_tracer
ls /proc/
------------[ cut here ]------------
[ 198.501417] Unable to handle kernel paging request at virtual address cb88537fdc8ba316
[ 198.506126] pgd = ffffffc008f79000
[ 198.509363] [cb88537fdc8ba316] *pgd=00000000488c6003, *pud=00000000488c6003, *pmd=0000000000000000
[ 198.517726] Internal error: Oops: 94000005 [#1] SMP
[ 198.518798] Modules linked in:
[ 198.520582] CPU: 1 PID: 1388 Comm: ls Tainted: G
[ 198.521800] Hardware name: linux,dummy-virt (DT)
[ 198.522852] task: ffffffc0fa9e8000 ti: ffffffc0f9ab0000 task.ti: ffffffc0f9ab0000
[ 198.524306] PC is at next_tgid+0x30/0x100
[ 198.525205] LR is at return_to_handler+0x0/0x20
[ 198.526090] pc : [<ffffffc0002a1070>] lr : [<ffffffc0000907c0>] pstate: 60000145
[ 198.527392] sp : ffffffc0f9ab3d40
[ 198.528084] x29: ffffffc0f9ab3d40 x28: ffffffc0f9ab0000
[ 198.529406] x27: ffffffc000d6a000 x26: ffffffc000b786e8
[ 198.530659] x25: ffffffc0002a1900 x24: ffffffc0faf16c00
[ 198.531942] x23: ffffffc0f9ab3ea0 x22: 0000000000000002
[ 198.533202] x21: ffffffc000d85050 x20: 0000000000000002
[ 198.534446] x19: 0000000000000002 x18: 0000000000000000
[ 198.535719] x17: 000000000049fa08 x16: ffffffc000242efc
[ 198.537030] x15: 0000007fa472b54c x14: ffffffffff000000
[ 198.538347] x13: ffffffc0fada84a0 x12: 0000000000000001
[ 198.539634] x11: ffffffc0f9ab3d70 x10: ffffffc0f9ab3d70
[ 198.540915] x9 : ffffffc0000907c0 x8 : ffffffc0f9ab3d40
[ 198.542215] x7 : 0000002e330f08f0 x6 : 0000000000000015
[ 198.543508] x5 : 0000000000000f08 x4 : ffffffc0f9835ec0
[ 198.544792] x3 : cb88537fdc8ba316 x2 : cb88537fdc8ba306
[ 198.546108] x1 : 0000000000000002 x0 : ffffffc000d85050
[ 198.547432]
[ 198.547920] Process ls (pid: 1388, stack limit = 0xffffffc0f9ab0020)
[ 198.549170] Stack: (0xffffffc0f9ab3d40 to 0xffffffc0f9ab4000)
[ 198.582568] Call trace:
[ 198.583313] [<ffffffc0002a1070>] next_tgid+0x30/0x100
[ 198.584359] [<ffffffc0000907bc>] ftrace_graph_caller+0x6c/0x70
[ 198.585503] [<ffffffc0000907bc>] ftrace_graph_caller+0x6c/0x70
[ 198.586574] [<ffffffc0000907bc>] ftrace_graph_caller+0x6c/0x70
[ 198.587660] [<ffffffc0000907bc>] ftrace_graph_caller+0x6c/0x70
[ 198.588896] Code: aa0003f5 2a0103f4 b4000102 91004043 (885f7c60)
[ 198.591092] ---[ end trace 6a346f8f20949ac8 ]---
This is because when using function graph tracer, if the traced
function return value is in multi regs ([x0-x7]), return_to_handler
may corrupt them. So in return_to_handler, the parameter regs should
be protected properly.
Cc: <stable@vger.kernel.org> # 3.18+
Signed-off-by: Li Bin <huawei.libin@huawei.com>
Acked-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/kernel/entry-ftrace.S | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S index 08cafc518b9a..0f03a8fe2314 100644 --- a/arch/arm64/kernel/entry-ftrace.S +++ b/arch/arm64/kernel/entry-ftrace.S @@ -178,6 +178,24 @@ ENTRY(ftrace_stub) ENDPROC(ftrace_stub) #ifdef CONFIG_FUNCTION_GRAPH_TRACER + /* save return value regs*/ + .macro save_return_regs + sub sp, sp, #64 + stp x0, x1, [sp] + stp x2, x3, [sp, #16] + stp x4, x5, [sp, #32] + stp x6, x7, [sp, #48] + .endm + + /* restore return value regs*/ + .macro restore_return_regs + ldp x0, x1, [sp] + ldp x2, x3, [sp, #16] + ldp x4, x5, [sp, #32] + ldp x6, x7, [sp, #48] + add sp, sp, #64 + .endm + /* * void ftrace_graph_caller(void) * @@ -204,11 +222,11 @@ ENDPROC(ftrace_graph_caller) * only when CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST is enabled. */ ENTRY(return_to_handler) - str x0, [sp, #-16]! + save_return_regs mov x0, x29 // parent's fp bl ftrace_return_to_handler// addr = ftrace_return_to_hander(fp); mov x30, x0 // restore the original return address - ldr x0, [sp], #16 + restore_return_regs ret END(return_to_handler) #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |