From 905b0297a9533d7a6ee00a01a990456636877dd6 Mon Sep 17 00:00:00 2001 From: Bian Yu Date: Sat, 12 Oct 2013 01:10:03 -0400 Subject: [PATCH] md: avoid deadlock when md_set_badblocks. When operate harddisk and hit errors, md_set_badblocks is called after scsi_restart_operations which already disabled the irq. but md_set_badblocks will call write_sequnlock_irq and enable irq. so softirq can preempt the current thread and that may cause a deadlock. I think this situation should use write_sequnlock_irqsave/irqrestore instead. I met the situation and the call trace is below: [ 638.919974] BUG: spinlock recursion on CPU#0, scsi_eh_13/1010 [ 638.921923] lock: 0xffff8800d4d51fc8, .magic: dead4ead, .owner: scsi_eh_13/1010, .owner_cpu: 0 [ 638.923890] CPU: 0 PID: 1010 Comm: scsi_eh_13 Not tainted 3.12.0-rc5+ #37 [ 638.925844] Hardware name: To be filled by O.E.M. To be filled by O.E.M./MAHOBAY, BIOS 4.6.5 03/05/2013 [ 638.927816] ffff880037ad4640 ffff880118c03d50 ffffffff8172ff85 0000000000000007 [ 638.929829] ffff8800d4d51fc8 ffff880118c03d70 ffffffff81730030 ffff8800d4d51fc8 [ 638.931848] ffffffff81a72eb0 ffff880118c03d90 ffffffff81730056 ffff8800d4d51fc8 [ 638.933884] Call Trace: [ 638.935867] [] dump_stack+0x55/0x76 [ 638.937878] [] spin_dump+0x8a/0x8f [ 638.939861] [] spin_bug+0x21/0x26 [ 638.941836] [] do_raw_spin_lock+0xa4/0xc0 [ 638.943801] [] _raw_spin_lock+0x66/0x80 [ 638.945747] [] ? scsi_device_unbusy+0x9d/0xd0 [ 638.947672] [] ? _raw_spin_unlock+0x2b/0x50 [ 638.949595] [] scsi_device_unbusy+0x9d/0xd0 [ 638.951504] [] scsi_finish_command+0x37/0xe0 [ 638.953388] [] scsi_softirq_done+0xa8/0x140 [ 638.955248] [] blk_done_softirq+0x7b/0x90 [ 638.957116] [] __do_softirq+0xfd/0x330 [ 638.958987] [] ? __lock_release+0x6f/0x100 [ 638.960861] [] call_softirq+0x1c/0x30 [ 638.962724] [] do_softirq+0x8d/0xc0 [ 638.964565] [] irq_exit+0x10e/0x150 [ 638.966390] [] smp_apic_timer_interrupt+0x4a/0x60 [ 638.968223] [] apic_timer_interrupt+0x6f/0x80 [ 638.970079] [] ? __lock_release+0x6f/0x100 [ 638.971899] [] ? _raw_spin_unlock_irq+0x3a/0x50 [ 638.973691] [] ? _raw_spin_unlock_irq+0x30/0x50 [ 638.975475] [] md_set_badblocks+0x1f3/0x4a0 [ 638.977243] [] rdev_set_badblocks+0x27/0x80 [ 638.978988] [] raid5_end_read_request+0x36b/0x4e0 [raid456] [ 638.980723] [] bio_endio+0x1d/0x40 [ 638.982463] [] req_bio_endio.isra.65+0x83/0xa0 [ 638.984214] [] blk_update_request+0x7f/0x350 [ 638.985967] [] blk_update_bidi_request+0x31/0x90 [ 638.987710] [] __blk_end_bidi_request+0x20/0x50 [ 638.989439] [] __blk_end_request_all+0x1f/0x30 [ 638.991149] [] blk_peek_request+0x106/0x250 [ 638.992861] [] ? scsi_kill_request.isra.32+0xe9/0x130 [ 638.994561] [] scsi_request_fn+0x4a/0x3d0 [ 638.996251] [] __blk_run_queue+0x37/0x50 [ 638.997900] [] blk_run_queue+0x2f/0x50 [ 638.999553] [] scsi_run_queue+0xe0/0x1c0 [ 639.001185] [] scsi_run_host_queues+0x21/0x40 [ 639.002798] [] scsi_restart_operations+0x177/0x200 [ 639.004391] [] scsi_error_handler+0xc9/0xe0 [ 639.005996] [] ? scsi_unjam_host+0xd0/0xd0 [ 639.007600] [] kthread+0xdb/0xe0 [ 639.009205] [] ? flush_kthread_worker+0x170/0x170 [ 639.010821] [] ret_from_fork+0x7c/0xb0 [ 639.012437] [] ? flush_kthread_worker+0x170/0x170 This bug was introduce in commit 2e8ac30312973dd20e68073653 (the first time rdev_set_badblock was call from interrupt context), so this patch is appropriate for 3.5 and subsequent kernels. Cc: (3.5+) Signed-off-by: Bian Yu Reviewed-by: Jianpeng Ma Signed-off-by: NeilBrown --- drivers/md/md.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index adf4d7e1d5e1..561a65f82e26 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8111,6 +8111,7 @@ static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors, u64 *p; int lo, hi; int rv = 1; + unsigned long flags; if (bb->shift < 0) /* badblocks are disabled */ @@ -8125,7 +8126,7 @@ static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors, sectors = next - s; } - write_seqlock_irq(&bb->lock); + write_seqlock_irqsave(&bb->lock, flags); p = bb->page; lo = 0; @@ -8241,7 +8242,7 @@ static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors, bb->changed = 1; if (!acknowledged) bb->unacked_exist = 1; - write_sequnlock_irq(&bb->lock); + write_sequnlock_irqrestore(&bb->lock, flags); return rv; } -- 2.39.5