The following commit has been merged into the refs/heads/perf/core branch of tip:
Commit-ID: e336b4027775cb458dc713745e526fa1a1996b2a Gitweb: https://git.kernel.org/tip/e336b4027775cb458dc713745e526fa1a1996b2a Author: Masami Hiramatsu <[email protected]> AuthorDate: Tue, 03 Sep 2019 20:08:21 +09:00 Committer: Ingo Molnar <[email protected]> CommitterDate: Thu, 05 Sep 2019 10:15:16 +02:00 kprobes: Prohibit probing on BUG() and WARN() address Since BUG() and WARN() may use a trap (e.g. UD2 on x86) to get the address where the BUG() has occurred, kprobes can not do single-step out-of-line that instruction. So prohibit probing on such address. Without this fix, if someone put a kprobe on WARN(), the kernel will crash with invalid opcode error instead of outputing warning message, because kernel can not find correct bug address. Signed-off-by: Masami Hiramatsu <[email protected]> Acked-by: Steven Rostedt (VMware) <[email protected]> Acked-by: Naveen N. Rao <[email protected]> Cc: Anil S Keshavamurthy <[email protected]> Cc: David S . Miller <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Naveen N . Rao <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: https://lkml.kernel.org/r/156750890133.19112.3393666300746167111.stgit@devnote2 Signed-off-by: Ingo Molnar <[email protected]> --- include/linux/bug.h | 5 +++++ kernel/kprobes.c | 3 ++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/include/linux/bug.h b/include/linux/bug.h index fe59165..f639bd0 100644 --- a/include/linux/bug.h +++ b/include/linux/bug.h @@ -47,6 +47,11 @@ void generic_bug_clear_once(void); #else /* !CONFIG_GENERIC_BUG */ +static inline void *find_bug(unsigned long bugaddr) +{ + return NULL; +} + static inline enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs) { diff --git a/kernel/kprobes.c b/kernel/kprobes.c index d9770a5..ebe8315 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1514,7 +1514,8 @@ static int check_kprobe_address_safe(struct kprobe *p, /* Ensure it is not in reserved area nor out of text */ if (!kernel_text_address((unsigned long) p->addr) || within_kprobe_blacklist((unsigned long) p->addr) || - jump_label_text_reserved(p->addr, p->addr)) { + jump_label_text_reserved(p->addr, p->addr) || + find_bug((unsigned long)p->addr)) { ret = -EINVAL; goto out; }
