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| author | Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de> | 2019-06-12 15:08:37 +0200 |
|---|---|---|
| committer | Yoshinori Sato <ysato@users.sourceforge.jp> | 2019-06-26 19:11:13 +0900 |
| commit | d3023897b4370bbf7f289806667a2380576d13dd (patch) | |
| tree | 33224cefb6689fd0b1317c1adf34763cf9dff903 /arch/sh | |
| parent | 7c04efc8d2efa6476cc4fc1228c1e20bdc4129ad (diff) | |
| download | lwn-d3023897b4370bbf7f289806667a2380576d13dd.tar.gz lwn-d3023897b4370bbf7f289806667a2380576d13dd.zip | |
arch/sh: Check for kprobe trap number before trying to handle a kprobe trap
The DIE_TRAP notifier chain is run both for kprobe traps and for BUG/WARN
traps. The kprobe code assumes to be only called for
BREAKPOINT_INSTRUCTION, and concludes to have hit a concurrently removed
kprobe if it finds anything else at the faulting locations. This includes
TRAPA_BUG_OPCODE used for BUG and WARN.
The consequence is that kprobe_handler returns 1. This makes
kprobe_exceptions_notify return NOTIFY_STOP, and prevents handling the BUG
statement. This also prevents moving $pc away from the trap instruction,
so the system locks up in an endless loop
Signed-off-by: Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de>
Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Diffstat (limited to 'arch/sh')
| -rw-r--r-- | arch/sh/kernel/kprobes.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/sh/kernel/kprobes.c b/arch/sh/kernel/kprobes.c index 1f8c0d30567f..318296f48f1a 100644 --- a/arch/sh/kernel/kprobes.c +++ b/arch/sh/kernel/kprobes.c @@ -485,7 +485,8 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); addr = (kprobe_opcode_t *) (args->regs->pc); - if (val == DIE_TRAP) { + if (val == DIE_TRAP && + args->trapnr == (BREAKPOINT_INSTRUCTION & 0xff)) { if (!kprobe_running()) { if (kprobe_handler(args->regs)) { ret = NOTIFY_STOP; |