Mark Rutland
2018-Feb-23 15:47 UTC
v4.16-rc2: virtio-block + ext4 lockdep splats / sleeping from invalid context
Hi all,
While fuzzing arm64/v4.16-rc2 with syzkaller, I simultaneously hit a
number of splats in the block layer:
* inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-R} usage in
jbd2_trans_will_send_data_barrier
* BUG: sleeping function called from invalid context at mm/mempool.c:320
* WARNING: CPU: 0 PID: 0 at block/blk.h:297
generic_make_request_checks+0x670/0x750
... I've included the full splats at the end of the mail.
These all happen in the context of the virtio block IRQ handler, so I
wonder if this calls something that doesn't expect to be called from IRQ
context. Is it valid to call blk_mq_complete_request() or
blk_mq_end_request() from an IRQ handler?
Syzkaller came up with a minimized reproducer, but it's a bit wacky (the
fcntl and bpf calls should have no practical effect), and I haven't
managed to come up with a C reproducer.
Any ideas?
Thanks,
Mark.
Syzkaller reproducer:
# {Threaded:true Collide:true Repeat:false Procs:1 Sandbox:setuid Fault:false
FaultCall:-1 FaultNth:0 EnableTun:true UseTmpDir:true HandleSegv:true
WaitRepeat:false Debug:false Repro:false}
mmap(&(0x7f0000000000/0x24000)=nil, 0x24000, 0x3, 0x32, 0xffffffffffffffff,
0x0)
r0 = openat(0xffffffffffffff9c, &(0x7f0000019000-0x8)='./file0\x00',
0x42, 0x0)
fcntl$setstatus(r0, 0x4, 0x10000)
ftruncate(r0, 0x400)
io_setup(0x1f, &(0x7f0000018000)=<r1=>0x0)
io_submit(r1, 0x1, &(0x7f000001d000-0x28)=[&(0x7f000001b000)={0x0, 0x0,
0x0, 0x1, 0x0, r0,
&(0x7f0000022000-0x1000)="0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
0x200, 0x0, 0x0, 0x0, 0x0}])
bpf$BPF_PROG_ATTACH(0xffffffff, &(0x7f000001b000)={0x0, 0x0, 0x3, 0x2},
0x40000000)
Full splat:
[ 162.337073] ===============================[ 162.338055] WARNING:
inconsistent lock state
[ 162.339017] 4.16.0-rc2 #1 Not tainted
[ 162.339797] --------------------------------
[ 162.340725] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-R} usage.
[ 162.342030] swapper/0/0 [HC1[1]:SC0[0]:HE0:SE1] takes:
[ 162.343061] (&journal->j_state_lock){+?++}, at:
[<000000003b9c3e4b>] jbd2_trans_will_send_data_barrier+0x44/0xc8
[ 162.353187] {HARDIRQ-ON-W} state was registered at:
[ 162.354433] lock_acquire+0x48/0x68
[ 162.358640] _raw_write_lock+0x3c/0x50
[ 162.360716] ext4_init_journal_params.isra.6+0x40/0xa0
[ 162.363445] ext4_fill_super+0x25cc/0x2e88
[ 162.364481] mount_bdev+0x19c/0x1d8
[ 162.365345] ext4_mount+0x14/0x20
[ 162.366130] mount_fs+0x34/0x160
[ 162.366790] vfs_kern_mount.part.8+0x54/0x160
[ 162.367874] do_mount+0x540/0xd40
[ 162.373776] SyS_mount+0x68/0x100
[ 162.374467] mount_block_root+0x11c/0x28c
[ 162.376558] mount_root+0x130/0x164
[ 162.380753] prepare_namespace+0x138/0x180
[ 162.381729] kernel_init_freeable+0x25c/0x280
[ 162.382625] kernel_init+0x10/0x100
[ 162.383337] ret_from_fork+0x10/0x18
[ 162.384072] irq event stamp: 3670810
[ 162.384787] hardirqs last enabled at (3670805): [<00000000fa98454e>]
arch_cpu_idle+0x14/0x28
[ 162.386505] hardirqs last disabled at (3670806): [<00000000341112e2>]
el1_irq+0x74/0x130
[ 162.388107] softirqs last enabled at (3670810): [<00000000d00bd211>]
_local_bh_enable+0x20/0x40
[ 162.389880] softirqs last disabled at (3670809): [<00000000e929005c>]
irq_enter+0x54/0x70
[ 162.391443]
[ 162.391443] other info that might help us debug this:
[ 162.392680] Possible unsafe locking scenario:
[ 162.392680]
[ 162.405967] CPU0
[ 162.406513] ----
[ 162.407055] lock(&journal->j_state_lock);
[ 162.407880] <Interrupt>
[ 162.408400] lock(&journal->j_state_lock);
[ 162.409287]
[ 162.409287] *** DEADLOCK ***
[ 162.409287]
[ 162.410447] 2 locks held by swapper/0/0:
[ 162.411248] #0: (&(&vblk->vqs[i].lock)->rlock){-.-.}, at:
[<00000000b75553ae>] virtblk_done+0x50/0xf8
[ 162.413101] #1: (rcu_read_lock){....}, at: [<000000002bf2a216>]
hctx_lock+0x1c/0xe8
[ 162.414630]
[ 162.414630] stack backtrace:
[ 162.415492] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0-rc2 #1
[ 162.429624] Hardware name: linux,dummy-virt (DT)
[ 162.430631] Call trace:
[ 162.431196] dump_backtrace+0x0/0x1c8
[ 162.432005] show_stack+0x14/0x20
[ 162.432747] dump_stack+0xac/0xe4
[ 162.433507] print_usage_bug.part.28+0x258/0x270
[ 162.434510] mark_lock+0x744/0x750
[ 162.435208] __lock_acquire+0xab8/0x18c0
[ 162.435982] lock_acquire+0x48/0x68
[ 162.436678] _raw_read_lock+0x3c/0x50
[ 162.449520] jbd2_trans_will_send_data_barrier+0x44/0xc8
[ 162.450681] ext4_sync_file+0x1e0/0x330
[ 162.451535] vfs_fsync_range+0x48/0xc0
[ 162.452323] dio_complete+0x1fc/0x220
[ 162.453094] dio_bio_end_aio+0xf0/0x130
[ 162.453935] bio_endio+0xe8/0xf8
[ 162.454625] blk_update_request+0x80/0x2e8
[ 162.455450] blk_mq_end_request+0x20/0x70
[ 162.456240] virtblk_request_done+0x24/0x30
[ 162.457080] __blk_mq_complete_request+0x100/0x1b0
[ 162.458047] blk_mq_complete_request+0x60/0x98
[ 162.458918] virtblk_done+0x70/0xf8
[ 162.459608] vring_interrupt+0x38/0x50
[ 162.460367] __handle_irq_event_percpu+0x5c/0x148
[ 162.472443] handle_irq_event_percpu+0x34/0x88
[ 162.477991] handle_irq_event+0x48/0x78
[ 162.480661] handle_fasteoi_irq+0xc0/0x198
[ 162.485417] generic_handle_irq+0x24/0x38
[ 162.490334] __handle_domain_irq+0x84/0xf0
[ 162.493834] gic_handle_irq+0x58/0xa8
[ 162.498464] el1_irq+0xb4/0x130
[ 162.500621] arch_cpu_idle+0x18/0x28
[ 162.504729] default_idle_call+0x1c/0x34
[ 162.508005] do_idle+0x17c/0x1f0
[ 162.510184] cpu_startup_entry+0x20/0x28
[ 162.515050] rest_init+0x250/0x260
[ 162.518228] start_kernel+0x3f0/0x41c
[ 162.522987] BUG: sleeping function called from invalid context at
mm/mempool.c:320
[ 162.533762] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/0
[ 162.540375] INFO: lockdep is turned off.
[ 162.542696] irq event stamp: 3670810
[ 162.544963] hardirqs last enabled at (3670805): [<00000000fa98454e>]
arch_cpu_idle+0x14/0x28
[ 162.551514] hardirqs last disabled at (3670806): [<00000000341112e2>]
el1_irq+0x74/0x130
[ 162.557422] softirqs last enabled at (3670810): [<00000000d00bd211>]
_local_bh_enable+0x20/0x40
[ 162.562596] softirqs last disabled at (3670809): [<00000000e929005c>]
irq_enter+0x54/0x70
[ 162.568863] Preemption disabled at:
[ 162.568877] [<ffff000008b59ca4>] schedule_preempt_disabled+0x1c/0x28
[ 162.574673] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0-rc2 #1
[ 162.580013] Hardware name: linux,dummy-virt (DT)
[ 162.583234] Call trace:
[ 162.585279] dump_backtrace+0x0/0x1c8
[ 162.587583] show_stack+0x14/0x20
[ 162.589047] dump_stack+0xac/0xe4
[ 162.592035] ___might_sleep+0x164/0x238
[ 162.594830] __might_sleep+0x50/0x88
[ 162.597012] mempool_alloc+0xc0/0x198
[ 162.600633] bio_alloc_bioset+0x144/0x250
[ 162.602983] blkdev_issue_flush+0x48/0xc8
[ 162.606134] ext4_sync_file+0x220/0x330
[ 162.607870] vfs_fsync_range+0x48/0xc0
[ 162.611694] dio_complete+0x1fc/0x220
[ 162.613369] dio_bio_end_aio+0xf0/0x130
[ 162.617040] bio_endio+0xe8/0xf8
[ 162.618583] blk_update_request+0x80/0x2e8
[ 162.619841] blk_mq_end_request+0x20/0x70
[ 162.621082] virtblk_request_done+0x24/0x30
[ 162.627389] __blk_mq_complete_request+0x100/0x1b0
[ 162.630482] blk_mq_complete_request+0x60/0x98
[ 162.633003] virtblk_done+0x70/0xf8
[ 162.635456] vring_interrupt+0x38/0x50
[ 162.638588] __handle_irq_event_percpu+0x5c/0x148
[ 162.640582] handle_irq_event_percpu+0x34/0x88
[ 162.642829] handle_irq_event+0x48/0x78
[ 162.644062] handle_fasteoi_irq+0xc0/0x198
[ 162.646182] generic_handle_irq+0x24/0x38
[ 162.648024] __handle_domain_irq+0x84/0xf0
[ 162.650304] gic_handle_irq+0x58/0xa8
[ 162.652917] el1_irq+0xb4/0x130
[ 162.656972] arch_cpu_idle+0x18/0x28
[ 162.658445] default_idle_call+0x1c/0x34
[ 162.660723] do_idle+0x17c/0x1f0
[ 162.664958] cpu_startup_entry+0x20/0x28
[ 162.670009] rest_init+0x250/0x260
[ 162.672763] start_kernel+0x3f0/0x41c
[ 162.677064] WARNING: CPU: 0 PID: 0 at block/blk.h:297
generic_make_request_checks+0x670/0x750
[ 162.682622] Kernel panic - not syncing: panic_on_warn set ...
[ 162.682622]
[ 162.695097] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W
4.16.0-rc2 #1
[ 162.700355] Hardware name: linux,dummy-virt (DT)
[ 162.713462] Call trace:
[ 162.714859] dump_backtrace+0x0/0x1c8
[ 162.722935] show_stack+0x14/0x20
[ 162.725392] dump_stack+0xac/0xe4
[ 162.727719] panic+0x13c/0x2b8
[ 162.732313] panic+0x0/0x2b8
[ 162.735233] report_bug+0xb4/0x158
[ 162.738377] bug_handler+0x30/0x88
[ 162.740810] brk_handler+0xd8/0x198
[ 162.747677] do_debug_exception+0x9c/0x190
[ 162.752011] el1_dbg+0x18/0x78
[ 162.755197] generic_make_request_checks+0x670/0x750
[ 162.761260] generic_make_request+0x2c/0x278
[ 162.764366] submit_bio+0x54/0x208
[ 162.771402] submit_bio_wait+0x68/0xa0
[ 162.775053] blkdev_issue_flush+0x8c/0xc8
[ 162.780520] ext4_sync_file+0x220/0x330
[ 162.784815] vfs_fsync_range+0x48/0xc0
[ 162.788243] dio_complete+0x1fc/0x220
[ 162.792071] dio_bio_end_aio+0xf0/0x130
[ 162.794820] bio_endio+0xe8/0xf8
[ 162.796203] blk_update_request+0x80/0x2e8
[ 162.800883] blk_mq_end_request+0x20/0x70
[ 162.803072] virtblk_request_done+0x24/0x30
[ 162.806877] __blk_mq_complete_request+0x100/0x1b0
[ 162.809298] blk_mq_complete_request+0x60/0x98
[ 162.811408] virtblk_done+0x70/0xf8
[ 162.812461] vring_interrupt+0x38/0x50
[ 162.813467] __handle_irq_event_percpu+0x5c/0x148
[ 162.814657] handle_irq_event_percpu+0x34/0x88
[ 162.815730] handle_irq_event+0x48/0x78
[ 162.816856] handle_fasteoi_irq+0xc0/0x198
[ 162.817946] generic_handle_irq+0x24/0x38
[ 162.818948] __handle_domain_irq+0x84/0xf0
[ 162.820056] gic_handle_irq+0x58/0xa8
[ 162.821013] el1_irq+0xb4/0x130
[ 162.826572] arch_cpu_idle+0x18/0x28
[ 162.827304] default_idle_call+0x1c/0x34
[ 162.828315] do_idle+0x17c/0x1f0
[ 162.829174] cpu_startup_entry+0x20/0x28
[ 162.830072] rest_init+0x250/0x260
[ 162.830872] start_kernel+0x3f0/0x41c
[ 162.831627] SMP: stopping secondary CPUs
[ 165.929235] SMP: failed to stop secondary CPUs 0,2
[ 165.949001] Kernel Offset: disabled
[ 165.963649] CPU features: 0x1802082
[ 165.969405] Memory Limit: none
[ 165.974480] Rebooting in 86400 seconds..
Jan Kara
2018-Feb-26 10:52 UTC
v4.16-rc2: virtio-block + ext4 lockdep splats / sleeping from invalid context
On Fri 23-02-18 15:47:36, Mark Rutland wrote:> Hi all, > > While fuzzing arm64/v4.16-rc2 with syzkaller, I simultaneously hit a > number of splats in the block layer: > > * inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-R} usage in > jbd2_trans_will_send_data_barrier > > * BUG: sleeping function called from invalid context at mm/mempool.c:320 > > * WARNING: CPU: 0 PID: 0 at block/blk.h:297 generic_make_request_checks+0x670/0x750 > > ... I've included the full splats at the end of the mail. > > These all happen in the context of the virtio block IRQ handler, so I > wonder if this calls something that doesn't expect to be called from IRQ > context. Is it valid to call blk_mq_complete_request() or > blk_mq_end_request() from an IRQ handler?No, it's likely a bug in detection whether IO completion should be deferred to a workqueue or not. Does attached patch fix the problem? I don't see exactly this being triggered by the syzkaller but it's close enough :) Honza> Syzkaller came up with a minimized reproducer, but it's a bit wacky (the > fcntl and bpf calls should have no practical effect), and I haven't > managed to come up with a C reproducer. > > Any ideas? > > Thanks, > Mark. > > > Syzkaller reproducer: > # {Threaded:true Collide:true Repeat:false Procs:1 Sandbox:setuid Fault:false FaultCall:-1 FaultNth:0 EnableTun:true UseTmpDir:true HandleSegv:true WaitRepeat:false Debug:false Repro:false} > mmap(&(0x7f0000000000/0x24000)=nil, 0x24000, 0x3, 0x32, 0xffffffffffffffff, 0x0) > r0 = openat(0xffffffffffffff9c, &(0x7f0000019000-0x8)='./file0\x00', 0x42, 0x0) > fcntl$setstatus(r0, 0x4, 0x10000) > ftruncate(r0, 0x400) > io_setup(0x1f, &(0x7f0000018000)=<r1=>0x0) > io_submit(r1, 0x1, &(0x7f000001d000-0x28)=[&(0x7f000001b000)={0x0, 0x0, 0x0, 0x1, 0x0, r0, &(0x7f0000022000-0x1000)="00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 > 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", 0x200, 0x0, 0x0, 0x0, 0x0}]) > bpf$BPF_PROG_ATTACH(0xffffffff, &(0x7f000001b000)={0x0, 0x0, 0x3, 0x2}, 0x40000000) > > > Full splat: > [ 162.337073] ===============================> [ 162.338055] WARNING: inconsistent lock state > [ 162.339017] 4.16.0-rc2 #1 Not tainted > [ 162.339797] -------------------------------- > [ 162.340725] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-R} usage. > [ 162.342030] swapper/0/0 [HC1[1]:SC0[0]:HE0:SE1] takes: > [ 162.343061] (&journal->j_state_lock){+?++}, at: [<000000003b9c3e4b>] jbd2_trans_will_send_data_barrier+0x44/0xc8 > [ 162.353187] {HARDIRQ-ON-W} state was registered at: > [ 162.354433] lock_acquire+0x48/0x68 > [ 162.358640] _raw_write_lock+0x3c/0x50 > [ 162.360716] ext4_init_journal_params.isra.6+0x40/0xa0 > [ 162.363445] ext4_fill_super+0x25cc/0x2e88 > [ 162.364481] mount_bdev+0x19c/0x1d8 > [ 162.365345] ext4_mount+0x14/0x20 > [ 162.366130] mount_fs+0x34/0x160 > [ 162.366790] vfs_kern_mount.part.8+0x54/0x160 > [ 162.367874] do_mount+0x540/0xd40 > [ 162.373776] SyS_mount+0x68/0x100 > [ 162.374467] mount_block_root+0x11c/0x28c > [ 162.376558] mount_root+0x130/0x164 > [ 162.380753] prepare_namespace+0x138/0x180 > [ 162.381729] kernel_init_freeable+0x25c/0x280 > [ 162.382625] kernel_init+0x10/0x100 > [ 162.383337] ret_from_fork+0x10/0x18 > [ 162.384072] irq event stamp: 3670810 > [ 162.384787] hardirqs last enabled at (3670805): [<00000000fa98454e>] arch_cpu_idle+0x14/0x28 > [ 162.386505] hardirqs last disabled at (3670806): [<00000000341112e2>] el1_irq+0x74/0x130 > [ 162.388107] softirqs last enabled at (3670810): [<00000000d00bd211>] _local_bh_enable+0x20/0x40 > [ 162.389880] softirqs last disabled at (3670809): [<00000000e929005c>] irq_enter+0x54/0x70 > [ 162.391443] > [ 162.391443] other info that might help us debug this: > [ 162.392680] Possible unsafe locking scenario: > [ 162.392680] > [ 162.405967] CPU0 > [ 162.406513] ---- > [ 162.407055] lock(&journal->j_state_lock); > [ 162.407880] <Interrupt> > [ 162.408400] lock(&journal->j_state_lock); > [ 162.409287] > [ 162.409287] *** DEADLOCK *** > [ 162.409287] > [ 162.410447] 2 locks held by swapper/0/0: > [ 162.411248] #0: (&(&vblk->vqs[i].lock)->rlock){-.-.}, at: [<00000000b75553ae>] virtblk_done+0x50/0xf8 > [ 162.413101] #1: (rcu_read_lock){....}, at: [<000000002bf2a216>] hctx_lock+0x1c/0xe8 > [ 162.414630] > [ 162.414630] stack backtrace: > [ 162.415492] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0-rc2 #1 > [ 162.429624] Hardware name: linux,dummy-virt (DT) > [ 162.430631] Call trace: > [ 162.431196] dump_backtrace+0x0/0x1c8 > [ 162.432005] show_stack+0x14/0x20 > [ 162.432747] dump_stack+0xac/0xe4 > [ 162.433507] print_usage_bug.part.28+0x258/0x270 > [ 162.434510] mark_lock+0x744/0x750 > [ 162.435208] __lock_acquire+0xab8/0x18c0 > [ 162.435982] lock_acquire+0x48/0x68 > [ 162.436678] _raw_read_lock+0x3c/0x50 > [ 162.449520] jbd2_trans_will_send_data_barrier+0x44/0xc8 > [ 162.450681] ext4_sync_file+0x1e0/0x330 > [ 162.451535] vfs_fsync_range+0x48/0xc0 > [ 162.452323] dio_complete+0x1fc/0x220 > [ 162.453094] dio_bio_end_aio+0xf0/0x130 > [ 162.453935] bio_endio+0xe8/0xf8 > [ 162.454625] blk_update_request+0x80/0x2e8 > [ 162.455450] blk_mq_end_request+0x20/0x70 > [ 162.456240] virtblk_request_done+0x24/0x30 > [ 162.457080] __blk_mq_complete_request+0x100/0x1b0 > [ 162.458047] blk_mq_complete_request+0x60/0x98 > [ 162.458918] virtblk_done+0x70/0xf8 > [ 162.459608] vring_interrupt+0x38/0x50 > [ 162.460367] __handle_irq_event_percpu+0x5c/0x148 > [ 162.472443] handle_irq_event_percpu+0x34/0x88 > [ 162.477991] handle_irq_event+0x48/0x78 > [ 162.480661] handle_fasteoi_irq+0xc0/0x198 > [ 162.485417] generic_handle_irq+0x24/0x38 > [ 162.490334] __handle_domain_irq+0x84/0xf0 > [ 162.493834] gic_handle_irq+0x58/0xa8 > [ 162.498464] el1_irq+0xb4/0x130 > [ 162.500621] arch_cpu_idle+0x18/0x28 > [ 162.504729] default_idle_call+0x1c/0x34 > [ 162.508005] do_idle+0x17c/0x1f0 > [ 162.510184] cpu_startup_entry+0x20/0x28 > [ 162.515050] rest_init+0x250/0x260 > [ 162.518228] start_kernel+0x3f0/0x41c > [ 162.522987] BUG: sleeping function called from invalid context at mm/mempool.c:320 > [ 162.533762] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/0 > [ 162.540375] INFO: lockdep is turned off. > [ 162.542696] irq event stamp: 3670810 > [ 162.544963] hardirqs last enabled at (3670805): [<00000000fa98454e>] arch_cpu_idle+0x14/0x28 > [ 162.551514] hardirqs last disabled at (3670806): [<00000000341112e2>] el1_irq+0x74/0x130 > [ 162.557422] softirqs last enabled at (3670810): [<00000000d00bd211>] _local_bh_enable+0x20/0x40 > [ 162.562596] softirqs last disabled at (3670809): [<00000000e929005c>] irq_enter+0x54/0x70 > [ 162.568863] Preemption disabled at: > [ 162.568877] [<ffff000008b59ca4>] schedule_preempt_disabled+0x1c/0x28 > [ 162.574673] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0-rc2 #1 > [ 162.580013] Hardware name: linux,dummy-virt (DT) > [ 162.583234] Call trace: > [ 162.585279] dump_backtrace+0x0/0x1c8 > [ 162.587583] show_stack+0x14/0x20 > [ 162.589047] dump_stack+0xac/0xe4 > [ 162.592035] ___might_sleep+0x164/0x238 > [ 162.594830] __might_sleep+0x50/0x88 > [ 162.597012] mempool_alloc+0xc0/0x198 > [ 162.600633] bio_alloc_bioset+0x144/0x250 > [ 162.602983] blkdev_issue_flush+0x48/0xc8 > [ 162.606134] ext4_sync_file+0x220/0x330 > [ 162.607870] vfs_fsync_range+0x48/0xc0 > [ 162.611694] dio_complete+0x1fc/0x220 > [ 162.613369] dio_bio_end_aio+0xf0/0x130 > [ 162.617040] bio_endio+0xe8/0xf8 > [ 162.618583] blk_update_request+0x80/0x2e8 > [ 162.619841] blk_mq_end_request+0x20/0x70 > [ 162.621082] virtblk_request_done+0x24/0x30 > [ 162.627389] __blk_mq_complete_request+0x100/0x1b0 > [ 162.630482] blk_mq_complete_request+0x60/0x98 > [ 162.633003] virtblk_done+0x70/0xf8 > [ 162.635456] vring_interrupt+0x38/0x50 > [ 162.638588] __handle_irq_event_percpu+0x5c/0x148 > [ 162.640582] handle_irq_event_percpu+0x34/0x88 > [ 162.642829] handle_irq_event+0x48/0x78 > [ 162.644062] handle_fasteoi_irq+0xc0/0x198 > [ 162.646182] generic_handle_irq+0x24/0x38 > [ 162.648024] __handle_domain_irq+0x84/0xf0 > [ 162.650304] gic_handle_irq+0x58/0xa8 > [ 162.652917] el1_irq+0xb4/0x130 > [ 162.656972] arch_cpu_idle+0x18/0x28 > [ 162.658445] default_idle_call+0x1c/0x34 > [ 162.660723] do_idle+0x17c/0x1f0 > [ 162.664958] cpu_startup_entry+0x20/0x28 > [ 162.670009] rest_init+0x250/0x260 > [ 162.672763] start_kernel+0x3f0/0x41c > [ 162.677064] WARNING: CPU: 0 PID: 0 at block/blk.h:297 generic_make_request_checks+0x670/0x750 > [ 162.682622] Kernel panic - not syncing: panic_on_warn set ... > [ 162.682622] > [ 162.695097] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 4.16.0-rc2 #1 > [ 162.700355] Hardware name: linux,dummy-virt (DT) > [ 162.713462] Call trace: > [ 162.714859] dump_backtrace+0x0/0x1c8 > [ 162.722935] show_stack+0x14/0x20 > [ 162.725392] dump_stack+0xac/0xe4 > [ 162.727719] panic+0x13c/0x2b8 > [ 162.732313] panic+0x0/0x2b8 > [ 162.735233] report_bug+0xb4/0x158 > [ 162.738377] bug_handler+0x30/0x88 > [ 162.740810] brk_handler+0xd8/0x198 > [ 162.747677] do_debug_exception+0x9c/0x190 > [ 162.752011] el1_dbg+0x18/0x78 > [ 162.755197] generic_make_request_checks+0x670/0x750 > [ 162.761260] generic_make_request+0x2c/0x278 > [ 162.764366] submit_bio+0x54/0x208 > [ 162.771402] submit_bio_wait+0x68/0xa0 > [ 162.775053] blkdev_issue_flush+0x8c/0xc8 > [ 162.780520] ext4_sync_file+0x220/0x330 > [ 162.784815] vfs_fsync_range+0x48/0xc0 > [ 162.788243] dio_complete+0x1fc/0x220 > [ 162.792071] dio_bio_end_aio+0xf0/0x130 > [ 162.794820] bio_endio+0xe8/0xf8 > [ 162.796203] blk_update_request+0x80/0x2e8 > [ 162.800883] blk_mq_end_request+0x20/0x70 > [ 162.803072] virtblk_request_done+0x24/0x30 > [ 162.806877] __blk_mq_complete_request+0x100/0x1b0 > [ 162.809298] blk_mq_complete_request+0x60/0x98 > [ 162.811408] virtblk_done+0x70/0xf8 > [ 162.812461] vring_interrupt+0x38/0x50 > [ 162.813467] __handle_irq_event_percpu+0x5c/0x148 > [ 162.814657] handle_irq_event_percpu+0x34/0x88 > [ 162.815730] handle_irq_event+0x48/0x78 > [ 162.816856] handle_fasteoi_irq+0xc0/0x198 > [ 162.817946] generic_handle_irq+0x24/0x38 > [ 162.818948] __handle_domain_irq+0x84/0xf0 > [ 162.820056] gic_handle_irq+0x58/0xa8 > [ 162.821013] el1_irq+0xb4/0x130 > [ 162.826572] arch_cpu_idle+0x18/0x28 > [ 162.827304] default_idle_call+0x1c/0x34 > [ 162.828315] do_idle+0x17c/0x1f0 > [ 162.829174] cpu_startup_entry+0x20/0x28 > [ 162.830072] rest_init+0x250/0x260 > [ 162.830872] start_kernel+0x3f0/0x41c > [ 162.831627] SMP: stopping secondary CPUs > [ 165.929235] SMP: failed to stop secondary CPUs 0,2 > [ 165.949001] Kernel Offset: disabled > [ 165.963649] CPU features: 0x1802082 > [ 165.969405] Memory Limit: none > [ 165.974480] Rebooting in 86400 seconds..-- Jan Kara <jack at suse.com> SUSE Labs, CR -------------- 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Mark Rutland
2018-Feb-26 11:38 UTC
v4.16-rc2: virtio-block + ext4 lockdep splats / sleeping from invalid context
On Mon, Feb 26, 2018 at 11:52:56AM +0100, Jan Kara wrote:> On Fri 23-02-18 15:47:36, Mark Rutland wrote: > > Hi all, > > > > While fuzzing arm64/v4.16-rc2 with syzkaller, I simultaneously hit a > > number of splats in the block layer: > > > > * inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-R} usage in > > jbd2_trans_will_send_data_barrier > > > > * BUG: sleeping function called from invalid context at mm/mempool.c:320 > > > > * WARNING: CPU: 0 PID: 0 at block/blk.h:297 generic_make_request_checks+0x670/0x750 > > > > ... I've included the full splats at the end of the mail. > > > > These all happen in the context of the virtio block IRQ handler, so I > > wonder if this calls something that doesn't expect to be called from IRQ > > context. Is it valid to call blk_mq_complete_request() or > > blk_mq_end_request() from an IRQ handler? > > No, it's likely a bug in detection whether IO completion should be deferred > to a workqueue or not. Does attached patch fix the problem? I don't see > exactly this being triggered by the syzkaller but it's close enough :) > > HonzaThat seems to be it! With the below patch applied, I can't trigger the bug after ~10 minutes, whereas prior to the patch I can trigger it in ~10 seconds. I'll leave that running for a while just in case there's another part to the problem, but FWIW: Tested-by: Mark Rutland <mark.rutland at arm.com> Thanks, Mark.> From 501d97ed88f5020a55a0de4d546df5ad11461cea Mon Sep 17 00:00:00 2001 > From: Jan Kara <jack at suse.cz> > Date: Mon, 26 Feb 2018 11:36:52 +0100 > Subject: [PATCH] direct-io: Fix sleep in atomic due to sync AIO > > Commit e864f39569f4 "fs: add RWF_DSYNC aand RWF_SYNC" added additional > way for direct IO to become synchronous and thus trigger fsync from the > IO completion handler. Then commit 9830f4be159b "fs: Use RWF_* flags for > AIO operations" allowed these flags to be set for AIO as well. However > that commit forgot to update the condition checking whether the IO > completion handling should be defered to a workqueue and thus AIO DIO > with RWF_[D]SYNC set will call fsync() from IRQ context resulting in > sleep in atomic. > > Fix the problem by checking directly iocb flags (the same way as it is > done in dio_complete()) instead of checking all conditions that could > lead to IO being synchronous. > > CC: Christoph Hellwig <hch at lst.de> > CC: Goldwyn Rodrigues <rgoldwyn at suse.com> > CC: stable at vger.kernel.org > Reported-by: Mark Rutland <mark.rutland at arm.com> > Fixes: 9830f4be159b29399d107bffb99e0132bc5aedd4 > Signed-off-by: Jan Kara <jack at suse.cz> > --- > fs/direct-io.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/fs/direct-io.c b/fs/direct-io.c > index a0ca9e48e993..1357ef563893 100644 > --- a/fs/direct-io.c > +++ b/fs/direct-io.c > @@ -1274,8 +1274,7 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, > */ > if (dio->is_async && iov_iter_rw(iter) == WRITE) { > retval = 0; > - if ((iocb->ki_filp->f_flags & O_DSYNC) || > - IS_SYNC(iocb->ki_filp->f_mapping->host)) > + if (iocb->ki_flags & IOCB_DSYNC) > retval = dio_set_defer_completion(dio); > else if (!dio->inode->i_sb->s_dio_done_wq) { > /* > -- > 2.13.6 >
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- v4.16-rc2: virtio-block + ext4 lockdep splats / sleeping from invalid context
- v4.16-rc2: virtio-block + ext4 lockdep splats / sleeping from invalid context