From 665ca9187c4087736fa57b0e00bcf33ea601fb6f Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Sun, 31 Jan 2016 14:23:30 +0100 Subject: [PATCH] s390/stacktrace: fix save_stack_trace_tsk() for current task The function save_stack_trace_tsk() did not consider that it can be used for tsk == current, for which the current stack pointer obviously cannot be found in the thread structure. Fix this and get the stack pointer with an inline assembly. This fixes e.g. the output of "cat /proc/self/stack". Before: [<0000000000000000>] (null) [] 0xffffffffffffffff After: [<000000000011b3ee>] save_stack_trace_tsk+0x56/0x98 [<0000000000366cde>] proc_pid_stack+0xae/0x108 [<00000000003636f0>] proc_single_show+0x70/0xc0 [<0000000000311fbc>] seq_read+0xcc/0x448 [<00000000002e7716>] __vfs_read+0x36/0x100 [<00000000002e872e>] vfs_read+0x76/0x130 [<00000000002e975e>] SyS_read+0x66/0xd8 [<000000000089490e>] system_call+0xd6/0x264 [] 0xffffffffffffffff Signed-off-by: Heiko Carstens Tested-by: Peter Oberparleiter Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/stacktrace.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c index 5acba3cb7220..dd484c75be56 100644 --- a/arch/s390/kernel/stacktrace.c +++ b/arch/s390/kernel/stacktrace.c @@ -86,6 +86,10 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) unsigned long sp, low, high; sp = tsk->thread.ksp; + if (tsk == current) { + /* Get current stack pointer. */ + asm volatile("la %0,0(15)" : "=a" (sp)); + } low = (unsigned long) task_stack_page(tsk); high = (unsigned long) task_pt_regs(tsk); save_context_stack(trace, sp, low, high, 0); -- 2.20.1