On Tue, Jan 09, 2024 at 02:50:20PM +0900, David Stevens wrote: > On Tue, Jan 9, 2024 at 6:50 AM Theodore Ts'o <tytso@xxxxxxx> wrote: > > > > Hi, while doing final testing before sending a pull request, I merged > > in linux-next, and commit 5b9ce7ecd7: virtio_balloon: stay awake while > > adjusting balloon seems to be causing a lockdep warning (see attached) > > when running gce-xfstests on a Google Compute Engine e2 VM. I was not > > able to trigger it using kvm-xfstests, but the following command: > > "gce-xfstests -C 10 ext4/4k generic/476) was sufficient to triger the > > problem. For more information please see [1] and [2]. > > > > [1] https://github.com/tytso/xfstests-bld/blob/master/Documentation/gce-xfstests.md > > [2] https://thunk.org/gce-xfstests > > > > I found it by looking at the git logs, and this commit aroused my > > suspicions, and I further testing showed that the lockdep warning was > > reproducible with this commit, but not when testing with the > > immediately preceeding commit (15b9ce7ecd^). > > > > Cheers, > > > > - Ted > > > > > > root: ext4/4k run xfstest generic/476 > > systemd[1]: Started fstests-generic-476.scope - /usr/bin/bash -c test -w /proc/self/oom_score_adj && echo 250 > /proc/self/oom_score_adj; exec ./tests/generic/476. > > kernel: [ 399.361181] EXT4-fs (dm-1): mounted filesystem 840e25bd-f650-4819-8562-7eded85ef370 r/w with ordered data mode. Quota mode: none. > > systemd[1]: fstests-generic-476.scope: Deactivated successfully. > > systemd[1]: fstests-generic-476.scope: Consumed 3min 1.966s CPU time. > > systemd[1]: xt\x2dvdb.mount: Deactivated successfully. > > kernel: [ 537.085404] EXT4-fs (dm-0): unmounting filesystem d3d7a675-f7b6-4384-abec-2e60d885b6da. > > systemd[1]: xt\x2dvdc.mount: Deactivated successfully. > > kernel: [ 540.565870] > > kernel: [ 540.567523] ================================ > > kernel: [ 540.572007] WARNING: inconsistent lock state > > kernel: [ 540.576407] 6.7.0-rc3-xfstests-lockdep-00012-g5b9ce7ecd715 #318 Not tainted > > kernel: [ 540.583532] -------------------------------- > > kernel: [ 540.587928] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. > > kernel: [ 540.594326] kworker/0:3/329 [HC0[0]:SC0[0]:HE1:SE1] takes: > > kernel: [ 540.599955] ffff90b280a548c0 (&vb->adjustment_lock){?...}-{2:2}, at: update_balloon_size_func+0x33/0x190 > > kernel: [ 540.609926] {IN-HARDIRQ-W} state was registered at: > > kernel: [ 540.614935] __lock_acquire+0x3f2/0xb30 > > kernel: [ 540.618992] lock_acquire+0xbf/0x2b0 > > kernel: [ 540.622786] _raw_spin_lock_irqsave+0x43/0x90 > > kernel: [ 540.627366] virtballoon_changed+0x51/0xd0 > > kernel: [ 540.631947] virtio_config_changed+0x5a/0x70 > > kernel: [ 540.636437] vp_config_changed+0x11/0x20 > > kernel: [ 540.640576] __handle_irq_event_percpu+0x88/0x230 > > kernel: [ 540.645500] handle_irq_event+0x38/0x80 > > kernel: [ 540.649558] handle_edge_irq+0x8f/0x1f0 > > kernel: [ 540.653791] __common_interrupt+0x47/0xf0 > > kernel: [ 540.658106] common_interrupt+0x79/0xa0 > > kernel: [ 540.661672] EXT4-fs (dm-1): unmounting filesystem 840e25bd-f650-4819-8562-7eded85ef370. > > kernel: [ 540.663183] asm_common_interrupt+0x26/0x40 > > kernel: [ 540.663190] acpi_safe_halt+0x1b/0x30 > > kernel: [ 540.663196] acpi_idle_enter+0x7b/0xd0 > > kernel: [ 540.663199] cpuidle_enter_state+0x90/0x4f0 > > kernel: [ 540.688723] cpuidle_enter+0x2d/0x40 > > kernel: [ 540.692516] cpuidle_idle_call+0xe4/0x120 > > kernel: [ 540.697036] do_idle+0x84/0xd0 > > kernel: [ 540.700393] cpu_startup_entry+0x2a/0x30 > > kernel: [ 540.704588] rest_init+0xe9/0x180 > > kernel: [ 540.708118] arch_call_rest_init+0xe/0x30 > > kernel: [ 540.712426] start_kernel+0x41c/0x4b0 > > kernel: [ 540.716310] x86_64_start_reservations+0x18/0x30 > > kernel: [ 540.721164] x86_64_start_kernel+0x8c/0x90 > > kernel: [ 540.725737] secondary_startup_64_no_verify+0x178/0x17b > > kernel: [ 540.731432] irq event stamp: 22681 > > kernel: [ 540.734956] hardirqs last enabled at (22681): [<ffffffff8b4b5158>] _raw_spin_unlock_irq+0x28/0x50 > > kernel: [ 540.744564] hardirqs last disabled at (22680): [<ffffffff8b4b4ded>] _raw_spin_lock_irq+0x5d/0x90 > > kernel: [ 540.753475] softirqs last enabled at (22076): [<ffffffff8a58cfa1>] srcu_invoke_callbacks+0x101/0x1c0 > > kernel: [ 540.762904] softirqs last disabled at (22072): [<ffffffff8a58cfa1>] srcu_invoke_callbacks+0x101/0x1c0 > > kernel: [ 540.773298] > > kernel: [ 540.773298] other info that might help us debug this: > > kernel: [ 540.780207] Possible unsafe locking scenario: > > kernel: [ 540.780207] > > kernel: [ 540.786438] CPU0 > > kernel: [ 540.789007] ---- > > kernel: [ 540.791766] lock(&vb->adjustment_lock); > > kernel: [ 540.796014] <Interrupt> > > kernel: [ 540.798778] lock(&vb->adjustment_lock); > > kernel: [ 540.803605] > > Oh, that's embarrassing, I completely whiffed on interactions with > interrupts. The following patch fixes it, and I've locally repro'ed > the issue and verified the fix. What's the process for getting this > fix merged? Does it get merged as a seperatch patch, or squashed into > the original commit? > > >From a99a1efa6a2b470a98ea2c87e58bebe90ce329a1 Mon Sep 17 00:00:00 2001 > From: David Stevens <stevensd@xxxxxxxxxxxx> > Date: Tue, 9 Jan 2024 14:41:21 +0900 > Subject: [PATCH] virtio_balloon: Fix interrupt context deadlock > > Use _irq spinlock functions with the adjustment_lock, since > start_update_balloon_size needs to acquire it in an interrupt context. > > Fixes: 5b9ce7ecd715 ("virtio_balloon: stay awake while adjusting balloon") > Reported-by: Theodore Ts'o <tytso@xxxxxxx> > Signed-off-by: David Stevens <stevensd@xxxxxxxxxxxx> > --- > drivers/virtio/virtio_balloon.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index aa6a1a649ad6..1f5b3dd31fcf 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -459,12 +459,12 @@ static void start_update_balloon_size(struct > virtio_balloon *vb) > > static void end_update_balloon_size(struct virtio_balloon *vb) > { > - spin_lock(&vb->adjustment_lock); > + spin_lock_irq(&vb->adjustment_lock); > if (!vb->adjustment_signal_pending && vb->adjustment_in_progress) { > vb->adjustment_in_progress = false; > pm_relax(vb->vdev->dev.parent); > } > - spin_unlock(&vb->adjustment_lock); > + spin_unlock_irq(&vb->adjustment_lock); > } > > static void virtballoon_changed(struct virtio_device *vdev) > @@ -506,9 +506,9 @@ static void update_balloon_size_func(struct > work_struct *work) > vb = container_of(work, struct virtio_balloon, > update_balloon_size_work); > > - spin_lock(&vb->adjustment_lock); > + spin_lock_irq(&vb->adjustment_lock); > vb->adjustment_signal_pending = false; > - spin_unlock(&vb->adjustment_lock); > + spin_unlock_irq(&vb->adjustment_lock); > > diff = towards_target(vb); Your patch is damaged (lines wrapped, sha info is wrong). Please post a new version of the original one I will replace it with the new one. -- MST
