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| author | Bernd Edlinger <bernd.edlinger@hotmail.de> | 2020-03-20 21:27:24 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-01 13:17:48 +0200 |
| commit | 4301db49e5569fbb729769bfaf9b21b858330543 (patch) | |
| tree | 4692e79595da237a47914e85491d007862ba9825 | |
| parent | 0cd97836869e9792cd66a2223b978f0148b46a12 (diff) | |
| download | linux-stable-4301db49e5569fbb729769bfaf9b21b858330543.tar.gz linux-stable-4301db49e5569fbb729769bfaf9b21b858330543.tar.bz2 linux-stable-4301db49e5569fbb729769bfaf9b21b858330543.zip | |
proc: Use new infrastructure to fix deadlocks in execve
[ Upstream commit 2db9dbf71bf98d02a0bf33e798e5bfd2a9944696 ]
This changes lock_trace to use the new exec_update_mutex
instead of cred_guard_mutex.
This fixes possible deadlocks when the trace is accessing
/proc/$pid/stack for instance.
This should be safe, as the credentials are only used for reading,
and task->mm is updated on execve under the new exec_update_mutex.
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>
| -rw-r--r-- | fs/proc/base.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index ebea9501afb8..4fdfe4faa74e 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -403,11 +403,11 @@ print0: static int lock_trace(struct task_struct *task) { - int err = mutex_lock_killable(&task->signal->cred_guard_mutex); + int err = mutex_lock_killable(&task->signal->exec_update_mutex); if (err) return err; if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) { - mutex_unlock(&task->signal->cred_guard_mutex); + mutex_unlock(&task->signal->exec_update_mutex); return -EPERM; } return 0; @@ -415,7 +415,7 @@ static int lock_trace(struct task_struct *task) static void unlock_trace(struct task_struct *task) { - mutex_unlock(&task->signal->cred_guard_mutex); + mutex_unlock(&task->signal->exec_update_mutex); } #ifdef CONFIG_STACKTRACE |