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author | Alan Cox <alan@lxorguk.ukuu.org.uk> | 2007-08-10 13:01:05 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-08-11 15:47:41 -0700 |
commit | 42fd552e8647316757ded0176466c41d17934dcf (patch) | |
tree | 07b0f4ed1934c05c6495c62ba943ab90bde6be84 /drivers/mtd | |
parent | docs: note about select in kconfig-language.txt (diff) | |
download | linux-dev-42fd552e8647316757ded0176466c41d17934dcf.tar.xz linux-dev-42fd552e8647316757ded0176466c41d17934dcf.zip |
fix serial buffer memory leak
Patch c5c34d4862e18ef07c1276d233507f540fb5a532 (tty: flush flip buffer on
ldisc input queue flush) introduces a race condition which can lead to memory
leaks.
The problem can be triggered when tcflush() is called when data are being
pushed to the line discipline driver by flush_to_ldisc().
flush_to_ldisc() releases tty->buf.lock when calling the line discipline
receive_buf function. At that poing tty_buffer_flush() kicks in and sets both
tty->buf.head and tty->buf.tail to NULL. When flush_to_ldisc() finishes, it
restores tty->buf.head but doesn't touch tty->buf.tail. This corrups the
buffer queue, and the next call to tty_buffer_request_room() will allocate a
new buffer and overwrite tty->buf.head. The previous buffer is then lost
forever without being released.
(Thanks to Laurent for the above text, for finding, disgnosing and reporting
the bug)
- Use tty->flags bits for the flush status.
- Wait for the flag to clear again before returning
- Fix the doc error noted
- Fix flush of empty queue leaving stale flushpending
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Alan Cox <alan@redhat.com>
Acked-by: Paul Fulghum <paulkf@microgate.com>
Cc: Laurent Pinchart <laurentp@cse-semaphore.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/mtd')
0 files changed, 0 insertions, 0 deletions