diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2015-07-21 15:40:23 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-07-31 10:38:05 +0200 |
| commit | a5b7e1a89b820f2b9b23634ca4c59b555e8d9a0d (patch) | |
| tree | 6c15eed109c9cc8982f428dc2d8a6b56b7aeb5fc /kernel/events | |
| parent | 5eeb50de42fd3251845d03c556db012267c72b3f (diff) | |
uprobes: Change prepare_uretprobe() to (try to) flush the dead frames
Change prepare_uretprobe() to flush the !arch_uretprobe_is_alive()
return_instance's. This is not needed correctness-wise, but can help
to avoid the failure caused by MAX_URETPROBE_DEPTH.
Note: in this case arch_uretprobe_is_alive() can be false
positive, the stack can grow after longjmp(). Unfortunately, the
kernel can't 100% solve this problem, but see the next patch.
Tested-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Anton Arapov <arapov@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150721134023.GA4776@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
| -rw-r--r-- | kernel/events/uprobes.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 93d939c80cd9..7e61c8ca27e0 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1511,6 +1511,16 @@ static unsigned long get_trampoline_vaddr(void) return trampoline_vaddr; } +static void cleanup_return_instances(struct uprobe_task *utask, struct pt_regs *regs) +{ + struct return_instance *ri = utask->return_instances; + while (ri && !arch_uretprobe_is_alive(ri, regs)) { + ri = free_ret_instance(ri); + utask->depth--; + } + utask->return_instances = ri; +} + static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs) { struct return_instance *ri; @@ -1541,6 +1551,9 @@ static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs) if (orig_ret_vaddr == -1) goto fail; + /* drop the entries invalidated by longjmp() */ + cleanup_return_instances(utask, regs); + /* * We don't want to keep trampoline address in stack, rather keep the * original return address of first caller thru all the consequent |