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| author |   Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2019-08-26 22:13:25 +0900 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-04 13:31:28 +0200 |
| commit | 8619e5bdeee8b2c685d686281f2d2a6017c4bc15 (patch) | |
| tree | 283230edb902e413d58a9b51f2e938d70aebb134 /drivers/firmware | |
| parent | binder: Add binder_proc logging to binderfs (diff) | |
| download | linux-dev-8619e5bdeee8b2c685d686281f2d2a6017c4bc15.tar.xz linux-dev-8619e5bdeee8b2c685d686281f2d2a6017c4bc15.zip | |
/dev/mem: Bail out upon SIGKILL.
syzbot found that a thread can stall for minutes inside read_mem() or
write_mem() after that thread was killed by SIGKILL [1]. Reading from
iomem areas of /dev/mem can be slow, depending on the hardware.
While reading 2GB at one read() is legal, delaying termination of killed
thread for minutes is bad. Thus, allow reading/writing /dev/mem and
/dev/kmem to be preemptible and killable.
[ 1335.912419][T20577] read_mem: sz=4096 count=2134565632
[ 1335.943194][T20577] read_mem: sz=4096 count=2134561536
[ 1335.978280][T20577] read_mem: sz=4096 count=2134557440
[ 1336.011147][T20577] read_mem: sz=4096 count=2134553344
[ 1336.041897][T20577] read_mem: sz=4096 count=2134549248
Theoretically, reading/writing /dev/mem and /dev/kmem can become
"interruptible". But this patch chose "killable". Future patch will make
them "interruptible" so that we can revert to "killable" if some program
regressed.
[1] https://syzkaller.appspot.com/bug?id=a0e3436829698d5824231251fad9d8e998f94f5e
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: stable <stable@vger.kernel.org>
Reported-by: syzbot <syzbot+8ab2d0f39fb79fe6ca40@syzkaller.appspotmail.com>
Link: https://lore.kernel.org/r/1566825205-10703-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/firmware')
0 files changed, 0 insertions, 0 deletions