NMI watchdog: Watchdog detected hard LOCKUP on cpu 6
RIP: 0010:native_queued_spin_lock_slowpath+0x20d/0x2b0
Call Trace:
dump_stack_lvl+0x57/0x81
validate_chain.cold+0x157/0x16a
__lock_acquire+0xbb1/0x1900
lock_acquire+0x1da/0x640
_raw_spin_lock_irqsave+0x43/0x90
ploop_allocate_cluster+0x12f/0x8c0 [ploop]
ploop_alloc_cluster.isra.0+0xf7/0x1f0 [ploop]
ploop_prepare_reloc_index_wb+0x2ab/0x4e0 [ploop]
ploop_grow_relocate_cluster+0x849/0xcc0 [ploop]
ploop_process_resize_cmd+0x65/0x430 [ploop]
ploop_resize+0x415/0x680 [ploop]
ploop_message+0x420/0xc90 [ploop]
target_message+0x453/0x5e0 [dm_mod]
ctl_ioctl+0x41f/0x6a0 [dm_mod]
dm_ctl_ioctl+0xa/0x20 [dm_mod]
__x64_sys_ioctl+0x12b/0x1a0
do_syscall_64+0x5c/0x90
entry_SYSCALL_64_after_hwframe+0x77/0xe1
ploop_prepare_reloc_index_wb() aquires ploop->bat_lock and calls
(holding the lock) ploop_alloc_cluster(), which also aquires
ploop->bat_lock => deadlock.
ploop_prepare_reloc_index_wb
spin_lock_irq(&ploop->bat_lock);
ploop_alloc_cluster
ploop_allocate_cluster
spin_lock_irqsave(&ploop->bat_lock, flags);
Let's move ploop_alloc_cluster() out of the bat_lock, this is safe as
MD_UPDATING bit checked and set under the lock protects us from parallel
ploop_alloc_cluster() execution for a pertucular md_page.
And if the function is called in parallel for different md_page, it's
also OK as new cluster is searched in the bitmask under the bat_lock, so
same cluster wil never be found and "allocated" in parallel.
Fixes: 9caa1af11b0a ("dm-ploop: fix and rework md updates")
https://virtuozzo.atlassian.net/browse/VSTOR-107975
Signed-off-by: Konstantin Khorenko <khore...@virtuozzo.com>
Feature: dm-ploop: ploop target driver
---
drivers/md/dm-ploop-map.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 35085a04ca5f..5a2ef5691405 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -2746,6 +2746,7 @@ int ploop_prepare_reloc_index_wb(struct ploop *ploop,
add_to_wblist = ploop_md_make_dirty(ploop, md);
piwb = md->piwb;
+ spin_unlock_irq(&ploop->bat_lock);
if (dst_clu) {
/*
@@ -2759,7 +2760,6 @@ int ploop_prepare_reloc_index_wb(struct ploop *ploop,
if (err)
goto out_reset;
}
- spin_unlock_irq(&ploop->bat_lock);
*ret_md = md;
*add_for_wb = add_to_wblist ? 1 : 0;
@@ -2768,6 +2768,7 @@ int ploop_prepare_reloc_index_wb(struct ploop *ploop,
out_reset:
ploop_break_bat_update(ploop, md, piwb);
+ spin_lock_irq(&ploop->bat_lock);
out_error:
if (add_to_wblist)
clear_bit(MD_DIRTY, &md->status);
--
2.43.5
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