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| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2019-09-05 23:50:30 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-09-18 12:24:55 +1000 |
| commit | 7c1bb6bbf75d8ca5ec878627d3170effcaf54f27 (patch) | |
| tree | b7c4423c0e4ed890806fa3ceecebe0458f6d79fd /arch/powerpc | |
| parent | 370011a27028d6f05e598ed6211a0ca2dc0213f7 (diff) | |
| download | blackbird-op-linux-7c1bb6bbf75d8ca5ec878627d3170effcaf54f27.tar.gz blackbird-op-linux-7c1bb6bbf75d8ca5ec878627d3170effcaf54f27.zip | |
powerpc: Use ftrace_graph_ret_addr() when unwinding
With support for HAVE_FUNCTION_GRAPH_RET_ADDR_PTR,
ftrace_graph_ret_addr() provides more robust unwinding when function
graph is in use. Update show_stack() to use the same.
With dump_stack() added to sysrq_sysctl_handler(), before this patch:
root@(none):/sys/kernel/debug/tracing# cat /proc/sys/kernel/sysrq
CPU: 0 PID: 218 Comm: cat Not tainted 5.3.0-rc7-00868-g8453ad4a078c-dirty #20
Call Trace:
[c0000000d1e13c30] [c00000000006ab98] return_to_handler+0x0/0x40 (dump_stack+0xe8/0x164) (unreliable)
[c0000000d1e13c80] [c000000000145680] sysrq_sysctl_handler+0x48/0xb8
[c0000000d1e13cd0] [c00000000006ab98] return_to_handler+0x0/0x40 (proc_sys_call_handler+0x274/0x2a0)
[c0000000d1e13d60] [c00000000006ab98] return_to_handler+0x0/0x40 (return_to_handler+0x0/0x40)
[c0000000d1e13d80] [c00000000006ab98] return_to_handler+0x0/0x40 (__vfs_read+0x3c/0x70)
[c0000000d1e13dd0] [c00000000006ab98] return_to_handler+0x0/0x40 (vfs_read+0xb8/0x1b0)
[c0000000d1e13e20] [c00000000006ab98] return_to_handler+0x0/0x40 (ksys_read+0x7c/0x140)
After this patch:
Call Trace:
[c0000000d1e33c30] [c00000000006ab58] return_to_handler+0x0/0x40 (dump_stack+0xe8/0x164) (unreliable)
[c0000000d1e33c80] [c000000000145680] sysrq_sysctl_handler+0x48/0xb8
[c0000000d1e33cd0] [c00000000006ab58] return_to_handler+0x0/0x40 (proc_sys_call_handler+0x274/0x2a0)
[c0000000d1e33d60] [c00000000006ab58] return_to_handler+0x0/0x40 (__vfs_read+0x3c/0x70)
[c0000000d1e33d80] [c00000000006ab58] return_to_handler+0x0/0x40 (vfs_read+0xb8/0x1b0)
[c0000000d1e33dd0] [c00000000006ab58] return_to_handler+0x0/0x40 (ksys_read+0x7c/0x140)
[c0000000d1e33e20] [c00000000006ab58] return_to_handler+0x0/0x40 (system_call+0x5c/0x68)
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/dc89c9a887121342d9c7819482c3dabdece2a323.1567707399.git.naveen.n.rao@linux.vnet.ibm.com
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/process.c | 19 |
1 files changed, 6 insertions, 13 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 24621e7e5033..f289bdd2b562 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -2047,10 +2047,8 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) int count = 0; int firstframe = 1; #ifdef CONFIG_FUNCTION_GRAPH_TRACER - struct ftrace_ret_stack *ret_stack; - extern void return_to_handler(void); - unsigned long rth = (unsigned long)return_to_handler; - int curr_frame = 0; + unsigned long ret_addr; + int ftrace_idx = 0; #endif if (tsk == NULL) @@ -2079,15 +2077,10 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) if (!firstframe || ip != lr) { printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip); #ifdef CONFIG_FUNCTION_GRAPH_TRACER - if ((ip == rth) && curr_frame >= 0) { - ret_stack = ftrace_graph_get_ret_stack(current, - curr_frame++); - if (ret_stack) - pr_cont(" (%pS)", - (void *)ret_stack->ret); - else - curr_frame = -1; - } + ret_addr = ftrace_graph_ret_addr(current, + &ftrace_idx, ip, stack); + if (ret_addr != ip) + pr_cont(" (%pS)", (void *)ret_addr); #endif if (firstframe) pr_cont(" (unreliable)"); |
