On 01/21/2008 03:47 PM, Chuck Ebbert wrote: > 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. >
The bug reporter has confirmed that booting with "noreplace-smp" prevents the kernel oops. -- 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/
