path: root/fs
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authorThilo-Alexander Ginkel <>2011-12-17 10:55:10 +0100
committerGreg Kroah-Hartman <>2012-01-12 11:33:46 -0800
commit53b63616b396f49775d4b2c4c3e6eab648a7833b (patch)
tree55e381d1e553de5c25a6588adb9738bc24cf4e8b /fs
parentcdd2a1dae5c70401ddcf4a868299fdd2f77ad380 (diff)
usb: cdc-acm: Fix acm_tty_hangup() vs. acm_tty_close() race
[Not upstream s it was fixed differently there for 3.3 with a much more "intrusive" rework of the driver - gregkh] There is a race condition involving acm_tty_hangup() and acm_tty_close() where hangup() would attempt to access tty->driver_data without proper locking and NULL checking after close() has potentially already set it to NULL. One possibility to (sporadically) trigger this behavior is to perform a suspend/resume cycle with a running WWAN data connection. This patch addresses the issue by introducing a NULL check for tty->driver_data in acm_tty_hangup() protected by open_mutex and exiting gracefully when hangup() is invoked on a device that has already been closed. Signed-off-by: Thilo-Alexander Ginkel <> Signed-off-by: Greg Kroah-Hartman <>
Diffstat (limited to 'fs')
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