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. Signed-off-by: Oleg Nesterov <[email protected]> --- 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 0dd7ff7..b6433fb 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1522,6 +1522,16 @@ 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->auret, 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; @@ -1576,6 +1586,9 @@ static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs) ri->orig_ret_vaddr = orig_ret_vaddr; ri->chained = chained; + if (utask->depth) /* drop the entries invalidated by longjmp() */ + cleanup_return_instances(utask, regs); + utask->depth++; ri->next = utask->return_instances; utask->return_instances = ri; -- 1.5.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
