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| author | Chengfeng Ye <dg573847474@gmail.com> | 2023-12-07 12:34:37 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-12-09 21:17:45 +0000 |
| commit | d5dba32b8f6cb39be708b726044ba30dbc088b30 (patch) | |
| tree | 4fdc081a10e22cf42a9ae95a7e55fbfac576e988 /drivers/atm | |
| parent | 1ae4cd3cbdd08287c56c4cc816ebf05eb6681a0f (diff) | |
| download | lwn-d5dba32b8f6cb39be708b726044ba30dbc088b30.tar.gz lwn-d5dba32b8f6cb39be708b726044ba30dbc088b30.zip | |
atm: solos-pci: Fix potential deadlock on &cli_queue_lock
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: 9c54004ea717 ("atm: Driver for Solos PCI ADSL2+ card.")
Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/atm')
| -rw-r--r-- | drivers/atm/solos-pci.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/atm/solos-pci.c b/drivers/atm/solos-pci.c index 94fbc3abe60e..95f768b28a5e 100644 --- a/drivers/atm/solos-pci.c +++ b/drivers/atm/solos-pci.c @@ -449,9 +449,9 @@ static ssize_t console_show(struct device *dev, struct device_attribute *attr, struct sk_buff *skb; unsigned int len; - spin_lock(&card->cli_queue_lock); + spin_lock_bh(&card->cli_queue_lock); skb = skb_dequeue(&card->cli_queue[SOLOS_CHAN(atmdev)]); - spin_unlock(&card->cli_queue_lock); + spin_unlock_bh(&card->cli_queue_lock); if(skb == NULL) return sprintf(buf, "No data.\n"); |