On Thu, Dec 14, 2023 at 12:36 AM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote: > > KMSAN generates the following false positives on s390x: > > [ 6.063666] DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled()) > [ ...] > [ 6.577050] Call Trace: > [ 6.619637] [<000000000690d2de>] check_flags+0x1fe/0x210 > [ 6.665411] ([<000000000690d2da>] check_flags+0x1fa/0x210) > [ 6.707478] [<00000000006cec1a>] lock_acquire+0x2ca/0xce0 > [ 6.749959] [<00000000069820ea>] _raw_spin_lock_irqsave+0xea/0x190 > [ 6.794912] [<00000000041fc988>] __stack_depot_save+0x218/0x5b0 > [ 6.838420] [<000000000197affe>] __msan_poison_alloca+0xfe/0x1a0 > [ 6.882985] [<0000000007c5827c>] start_kernel+0x70c/0xd50 > [ 6.927454] [<0000000000100036>] startup_continue+0x36/0x40 > > Between trace_hardirqs_on() and `stosm __mask, 3` lockdep thinks that > interrupts are on, but on the CPU they are still off. KMSAN > instrumentation takes spinlocks, giving lockdep a chance to see and > complain about this discrepancy. > > KMSAN instrumentation is inserted in order to poison the __mask > variable. Disable instrumentation in the respective functions. They are > very small and it's easy to see that no important metadata updates are > lost because of this. > > Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx> Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx>
