Looking at the oops report from this bug: [bugzilla] https://bugzilla.redhat.com/show_bug.cgi?id=429412 [oops] https://bugzilla.redhat.com/attachment.cgi?id=292260
It was an unhandled page fault (protection violation.) I tracked it down to the cmpxchg in this code: include/asm-x86/futex_32.h::futex_atomic_cmpxchg_inatomic() __asm__ __volatile__( "1: " LOCK_PREFIX "cmpxchgl %3, %1 \n" "2: .section .fixup, \"ax\" \n" "3: mov %2, %0 \n" " jmp 2b \n" " .previous \n" " .section __ex_table, \"a\" \n" " .align 8 \n" " .long 1b,3b \n" " .previous \n" There is a fixup, so this should never happen. But the lock instruction was replaced with a nop by the altinstruction code, and that makes the fixup address wrong. AFAICT we don't fix up the exception table when we replace a lock with a nop, which makes the fixup table point to the nop instead of the cmpxchg instruction and causes us to miss the fixup. -- 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/