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| author | Jiri Kosina <jkosina@suse.cz> | 2007-04-23 14:41:21 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-04-24 08:23:09 -0700 |
| commit | 4bf3631cdb012591667ab927fcd7719d92837833 (patch) | |
| tree | 25976c75042f3aa557a7bc8ece781ea4901acc62 /drivers/serial | |
| parent | c5408b88ecb8b7127334a34c55d4e0174434f4ec (diff) | |
| download | linux-4bf3631cdb012591667ab927fcd7719d92837833.tar.gz linux-4bf3631cdb012591667ab927fcd7719d92837833.tar.bz2 linux-4bf3631cdb012591667ab927fcd7719d92837833.zip | |
8250: fix possible deadlock between serial8250_handle_port() and serial8250_interrupt()
Commit 40b36daa introduced possibility that serial8250_backup_timeout() ->
serial8250_handle_port() locks port.lock without disabling irqs, thus
allowing deadlock against interrupt handler (port.lock is acquired in
serial8250_interrupt()).
Spotted by lockdep.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/serial')
| -rw-r--r-- | drivers/serial/8250.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index c0c472ac5311..90621c3312bc 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -1334,8 +1334,9 @@ static inline void serial8250_handle_port(struct uart_8250_port *up) { unsigned int status; + unsigned long flags; - spin_lock(&up->port.lock); + spin_lock_irqsave(&up->port.lock, flags); status = serial_inp(up, UART_LSR); @@ -1347,7 +1348,7 @@ serial8250_handle_port(struct uart_8250_port *up) if (status & UART_LSR_THRE) transmit_chars(up); - spin_unlock(&up->port.lock); + spin_unlock_irqrestore(&up->port.lock, flags); } /* |