Messages in this thread Patch in this message | | | From | Alexander Shishkin <> | Subject | [PATCH] x86/debug: Handle warnings before the notifier chain | Date | Mon, 24 Jul 2017 13:04:28 +0300 |
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Commit
9a93848fe787 ("x86/debug: Implement __WARN() using UD0")
turned warnings into UD0, but the fixup code only runs after the notify_die() chain. This is a problem, in particular, with kgdb, which kicks in as if it was a BUG().
Fix this by running the fixup code before the notifier chain in the invalid op handler path.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Weinberger <richard.weinberger@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: linux-kernel@vger.kernel.org --- arch/x86/kernel/traps.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index bf54309b85..b2157d4a53 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -221,9 +221,6 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str, if (fixup_exception(regs, trapnr)) return 0; - if (fixup_bug(regs, trapnr)) - return 0; - tsk->thread.error_code = error_code; tsk->thread.trap_nr = trapnr; die(str, regs, error_code); @@ -304,6 +301,13 @@ static void do_error_trap(struct pt_regs *regs, long error_code, char *str, RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU"); + /* + * WARN*()s end up here; fix them up before we call the + * notifier chain. + */ + if (!user_mode(regs) && fixup_bug(regs, trapnr)) + return; + if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) != NOTIFY_STOP) { cond_local_irq_enable(regs); -- 2.13.2
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