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| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2017-06-01 13:48:15 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-06-16 12:49:43 +0300 |
| commit | a9f8553e935f26cb5447f67e280946b0923cd2dc (patch) | |
| tree | 50d94ef8c3ffe08b34b9ae3e9993c140733b1a61 /arch/powerpc/kernel/kprobes.c | |
| parent | a093c92dc7f96a15de98ec8cfe38e6f7610a5969 (diff) | |
| download | linux-a9f8553e935f26cb5447f67e280946b0923cd2dc.tar.xz | |
powerpc/kprobes: Pause function_graph tracing during jprobes handling
This fixes a crash when function_graph and jprobes are used together.
This is essentially commit 237d28db036e ("ftrace/jprobes/x86: Fix
conflict between jprobes and function graph tracing"), but for powerpc.
Jprobes breaks function_graph tracing since the jprobe hook needs to use
jprobe_return(), which never returns back to the hook, but instead to
the original jprobe'd function. The solution is to momentarily pause
function_graph tracing before invoking the jprobe hook and re-enable it
when returning back to the original jprobe'd function.
Fixes: 6794c78243bf ("powerpc64: port of the function graph tracer")
Cc: stable@vger.kernel.org # v2.6.30+
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/kprobes.c')
| -rw-r--r-- | arch/powerpc/kernel/kprobes.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index fc4343514bed..5075a4d6f1d7 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -617,6 +617,15 @@ int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc); #endif + /* + * jprobes use jprobe_return() which skips the normal return + * path of the function, and this messes up the accounting of the + * function graph tracer. + * + * Pause function graph tracing while performing the jprobe function. + */ + pause_graph_tracing(); + return 1; } NOKPROBE_SYMBOL(setjmp_pre_handler); @@ -642,6 +651,8 @@ int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) * saved regs... */ memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs)); + /* It's OK to start function graph tracing again */ + unpause_graph_tracing(); preempt_enable_no_resched(); return 1; } |