mirror of https://gitee.com/openkylin/linux.git
bafefc0cf8
The coverity checker detected a use-after-free error in drivers/media/video/cpia2/cpia2_v4l.c::cpia2_close() (coverity error #1281). What happens is that we lock cam->busy_lock, then proceed to free resources, and in the case of (--cam->open_count == 0) we finish off by doing a kfree(cam) and then at the end of the function we do a mutex_unlock(&cam->busy_lock) which will explode since it'll dereference the free'd `cam' : ... mutex_lock(&cam->busy_lock); ... if (--cam->open_count == 0) { ... if (!cam->present) { video_unregister_device(dev); kfree(cam); } } mutex_unlock(&cam->busy_lock); <--- PROBLEM, cam no longer around. ... Since this only happens in the case of open_count going down to zero I don't see a problem with just releasing the mutex after unregistering the device and just before the kfree(). In this case there is nothing around that we can race against; we are in the release method, open_count is zero, (!cam->present) and the device has just been unregistered, so letting go of the mutex at this point looks safe to me. Patch below to implement that solution. Acked-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org> |
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| .. | ||
| Kconfig | ||
| Makefile | ||
| cpia2.h | ||
| cpia2_core.c | ||
| cpia2_registers.h | ||
| cpia2_usb.c | ||
| cpia2_v4l.c | ||
| cpia2dev.h | ||
| cpia2patch.h | ||