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authorLinus Torvalds <torvalds@linux-foundation.org>2020-04-02 11:22:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-04-02 11:22:17 -0700
commitd987ca1c6b7e22fbd30664111e85cec7aa66000d (patch)
treec8f03ffe5367f8352af5d4bd776966d5c63b9232 /kernel/exit.c
parent919dce24701f7b34681a6a1d3ef95c9f6c4fb1cc (diff)
parentd1e7fd6462ca9fc76650fbe6ca800e35b24267da (diff)
downloadlinux-d987ca1c6b7e22fbd30664111e85cec7aa66000d.tar.bz2
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull exec/proc updates from Eric Biederman: "This contains two significant pieces of work: the work to sort out proc_flush_task, and the work to solve a deadlock between strace and exec. Fixing proc_flush_task so that it no longer requires a persistent mount makes improvements to proc possible. The removal of the persistent mount solves an old regression that that caused the hidepid mount option to only work on remount not on mount. The regression was found and reported by the Android folks. This further allows Alexey Gladkov's work making proc mount options specific to an individual mount of proc to move forward. The work on exec starts solving a long standing issue with exec that it takes mutexes of blocking userspace applications, which makes exec extremely deadlock prone. For the moment this adds a second mutex with a narrower scope that handles all of the easy cases. Which makes the tricky cases easy to spot. With a little luck the code to solve those deadlocks will be ready by next merge window" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (25 commits) signal: Extend exec_id to 64bits pidfd: Use new infrastructure to fix deadlocks in execve perf: Use new infrastructure to fix deadlocks in execve proc: io_accounting: Use new infrastructure to fix deadlocks in execve proc: Use new infrastructure to fix deadlocks in execve kernel/kcmp.c: Use new infrastructure to fix deadlocks in execve kernel: doc: remove outdated comment cred.c mm: docs: Fix a comment in process_vm_rw_core selftests/ptrace: add test cases for dead-locks exec: Fix a deadlock in strace exec: Add exec_update_mutex to replace cred_guard_mutex exec: Move exec_mmap right after de_thread in flush_old_exec exec: Move cleanup of posix timers on exec out of de_thread exec: Factor unshare_sighand out of de_thread and call it separately exec: Only compute current once in flush_old_exec pid: Improve the comment about waiting in zap_pid_ns_processes proc: Remove the now unnecessary internal mount of proc uml: Create a private mount of proc for mconsole uml: Don't consult current to find the proc_mnt in mconsole_proc proc: Use a list of inodes to flush from proc ...
Diffstat (limited to 'kernel/exit.c')
-rw-r--r--kernel/exit.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index d70d47159640..389a88cb3081 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -182,6 +182,7 @@ void put_task_struct_rcu_user(struct task_struct *task)
void release_task(struct task_struct *p)
{
struct task_struct *leader;
+ struct pid *thread_pid;
int zap_leader;
repeat:
/* don't need to get the RCU readlock here - the process is dead and
@@ -190,11 +191,11 @@ repeat:
atomic_dec(&__task_cred(p)->user->processes);
rcu_read_unlock();
- proc_flush_task(p);
cgroup_release(p);
write_lock_irq(&tasklist_lock);
ptrace_release_task(p);
+ thread_pid = get_pid(p->thread_pid);
__exit_signal(p);
/*
@@ -217,6 +218,7 @@ repeat:
}
write_unlock_irq(&tasklist_lock);
+ proc_flush_pid(thread_pid);
release_thread(p);
put_task_struct_rcu_user(p);