Messages in this thread | | | From | Anton Volkov <> | Subject | Possible race in loop.ko | Date | Fri, 28 Jul 2017 18:55:49 +0300 |
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Hello. While searching for races in Linux kernel I've come across drivers/block/loop.ko module. Here is the question that I came up with while analyzing results. Lines are given using the info from Linux v4.12.
In loop_init function additional initialization happens after a successful call to misc_register() (loop.c: line 1961). Consider the following case:
Thread 1: Thread 2: loop_init() misc_register() loop_control_ioctl part_shift = 0 -> loop_add if (max_part > 0) { alloc_disk(1 << part_shift) part_shift = <greater than 0> ... }
In this case alloc_disk() will be called with 1 as a parameter although part_shift should have been greater than 0. Maybe it would be better to move the call to a misc_register() function a bit further down (at least so it could be after the part_shift initialization)?
Thank you for your time.
-- Anton Volkov Linux Verification Center, ISPRAS web: http://linuxtesting.org e-mail: avolkov@ispras.ru
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