lkml.org 
[lkml]   [2020]   [Sep]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.4 197/388] proc: io_accounting: Use new infrastructure to fix deadlocks in execve
    Date
    From: Bernd Edlinger <bernd.edlinger@hotmail.de>

    [ Upstream commit 76518d3798855242817e8a8ed76b2d72f4415624 ]

    This changes do_io_accounting to use the new exec_update_mutex
    instead of cred_guard_mutex.

    This fixes possible deadlocks when the trace is accessing
    /proc/$pid/io for instance.

    This should be safe, as the credentials are only used for reading.

    Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
    Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    fs/proc/base.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    diff --git a/fs/proc/base.c b/fs/proc/base.c
    index 4fdfe4faa74ee..529d0c6ec6f9c 100644
    --- a/fs/proc/base.c
    +++ b/fs/proc/base.c
    @@ -2770,7 +2770,7 @@ static int do_io_accounting(struct task_struct *task, struct seq_file *m, int wh
    unsigned long flags;
    int result;

    - result = mutex_lock_killable(&task->signal->cred_guard_mutex);
    + result = mutex_lock_killable(&task->signal->exec_update_mutex);
    if (result)
    return result;

    @@ -2806,7 +2806,7 @@ static int do_io_accounting(struct task_struct *task, struct seq_file *m, int wh
    result = 0;

    out_unlock:
    - mutex_unlock(&task->signal->cred_guard_mutex);
    + mutex_unlock(&task->signal->exec_update_mutex);
    return result;
    }

    --
    2.25.1


    \
     
     \ /
      Last update: 2020-09-29 14:04    [W:4.101 / U:0.032 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site