atm: solos-pci: Fix potential deadlock on &cli_queue_lock

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As &card->cli_queue_lock is acquired under softirq context along the
following call chain from solos_bh(), other acquisition of the same
lock inside process context should disable at least bh to avoid double
lock.

<deadlock #1>
console_show()
--> spin_lock(&card->cli_queue_lock)
<interrupt>
   --> solos_bh()
   --> spin_lock(&card->cli_queue_lock)

This flaw was found by an experimental static analysis tool I am
developing for irq-related deadlock.

To prevent the potential deadlock, the patch uses spin_lock_bh()
on the card->cli_queue_lock under process context code consistently
to prevent the possible deadlock scenario.

Fixes: 9c54004ea7 ("atm: Driver for Solos PCI ADSL2+ card.")
Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

...

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Chengfeng Ye 2023-12-07 12:34:37 +00:00 • committed by David S. Miller

parent 1ae4cd3cbd

commit d5dba32b8f

1 changed files with 2 additions and 2 deletions

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drivers/atm/solos-pci.c

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