Ingo Molnar wrote:
* Jeff Garzik <[EMAIL PROTECTED]> wrote:
After analyzing the elements that save_flags/cli/sti/restore_flags
were protecting, convert their usages to a global spinlock (the
easiest and most obvious next-step). There were some usages of flags
being intentionally cached, because the code already knew the state of
interrupts. These have been taken into account.
This allows us to remove CONFIG_BROKEN_ON_SMP. Completely untested.
regression for sale :-) The above patch, after sitting in -mm for
approximately 3 months, just went upstream today via commit
d9afa43532adf8a31b93c4c7601f and promptly broke tonight's x86.git
randconfig qa run via tons of these messages:
[ 3.768431] BUG: scheduling while atomic: swapper/1/0x00000002
[ 3.769430] 1 lock held by swapper/1:
[ 3.770437] #0: (riscom_lock){--..}, at: [<80389ceb>]
rc_release_drivers+0xe/0x33
[ 3.776430] Pid: 1, comm: swapper Not tainted 2.6.24 #14
[ 3.777428] [<801167d3>] __schedule_bug+0x6e/0x75
[ 3.779427] [<80756065>] schedule+0x35c/0x429
[ 3.781427] [<80103a0b>] ? restore_nocheck+0x12/0x15
[ 3.784427] [<80103a0b>] ? restore_nocheck+0x12/0x15
[ 3.786426] [<80756381>] schedule_timeout+0x69/0xa2
[ 3.788426] [<80758337>] ? _spin_unlock_irq+0x25/0x40
[ 3.790426] [<80755c0e>] wait_for_common+0x96/0x10d
[ 3.792425] [<80115edc>] ? default_wake_function+0x0/0xd
[ 3.794425] [<80755d07>] wait_for_completion+0x12/0x14
[ 3.796425] [<801282fe>] call_usermodehelper_exec+0x78/0x8c
[ 3.798424] [<8015a041>] ? slob_alloc+0xd8/0x1ad
[ 3.800424] [<80301640>] kobject_uevent_env+0x3ae/0x3c5
[ 3.802424] [<803ac361>] ? dev_uevent+0x0/0x25a
[ 3.804424] [<80301661>] kobject_uevent+0xa/0xc
[ 3.806423] [<803acc06>] device_del+0x139/0x15d
[ 3.808423] [<803acc58>] device_unregister+0x2e/0x3b
[ 3.810423] [<803acc8e>] device_destroy+0x29/0x2f
[ 3.812422] [<8035965f>] tty_unregister_device+0x18/0x1a
[ 3.814422] [<8035970b>] tty_unregister_driver+0xaa/0xf6
[ 3.816422] [<80389cf7>] rc_release_drivers+0x1a/0x33
[ 3.818421] [<80ac5e16>] riscom8_init_module+0x4ff/0x539
[ 3.820421] [<8012e76f>] ? ktime_get_ts+0x44/0x49
[ 3.822421] [<80aaf701>] kernel_init+0x9a/0x263
[ 3.824421] [<80ac5917>] ? riscom8_init_module+0x0/0x539
[ 3.827420] [<80aaf667>] ? kernel_init+0x0/0x263
[ 3.829420] [<8010455f>] kernel_thread_helper+0x7/0x18
[ 3.831419] =======================
This is unfortunately very low on the priority stack. I was a bit
surprised when it went in, honestly, since I hadn't gotten any "it
works" test reports yet... but that's my fault for not keeping akpm up
to date.
We'll want to revert this for 2.6.25 release, if it doesn't get fixed up.
Jeff
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