From: Masami Hiramatsu <mhiramat@xxxxxxxxxx> [ Upstream commit e336b4027775cb458dc713745e526fa1a1996b2a ] 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 <mhiramat@xxxxxxxxxx> Acked-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Acked-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@xxxxxxxxx> Cc: David S . Miller <davem@xxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Naveen N . Rao <naveen.n.rao@xxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/156750890133.19112.3393666300746167111.stgit@devnote2 Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 da4231c905c85..f485974177914 100644 --- a/include/linux/bug.h +++ b/include/linux/bug.h @@ -45,6 +45,11 @@ int is_valid_bugaddr(unsigned long addr); #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 c43bc2bc5b2ca..f7a4602a76f98 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1501,7 +1501,8 @@ 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; } -- 2.20.1
