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| author | Michael Bestas <mkbestas@lineageos.org> | 2020-04-14 16:18:14 +0300 |
|---|---|---|
| committer | Michael Bestas <mkbestas@lineageos.org> | 2020-04-14 18:41:04 +0300 |
| commit | 9eb199e06bc76fb2677052c3a171b2ab917c121d (patch) | |
| tree | d92fe8bf4acb7ed72bb329b4191bc2bc7f222d73 /kernel/signal.c | |
| parent | 268d6e9ab66bfd7a826050a9a651cdd6bca2f773 (diff) | |
| parent | f9991115f079363d70ce91c37d850ec4a5e065a6 (diff) | |
Merge branch 'android-4.4-p' of https://android.googlesource.com/kernel/common into lineage-17.1-caf-msm8998
This brings LA.UM.8.4.r1-05300-8x98.0 up to date with
https://android.googlesource.com/kernel/common/ android-4.4-p at commit:
f9991115f0793 Merge 4.4.219 into android-4.4-p
Conflicts:
drivers/clk/qcom/clk-rcg2.c
drivers/scsi/sd.c
drivers/usb/gadget/function/f_fs.c
drivers/usb/gadget/function/u_serial.c
Change-Id: Ifed3db0ddda828c1697e57e9f73c1b73354bebf7
Diffstat (limited to 'kernel/signal.c')
| -rw-r--r-- | kernel/signal.c | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index 7e4a4b199a11..90a94e54db09 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -373,27 +373,32 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimi { struct sigqueue *q = NULL; struct user_struct *user; + int sigpending; /* * Protect access to @t credentials. This can go away when all * callers hold rcu read lock. + * + * NOTE! A pending signal will hold on to the user refcount, + * and we get/put the refcount only when the sigpending count + * changes from/to zero. */ rcu_read_lock(); - user = get_uid(__task_cred(t)->user); - atomic_inc(&user->sigpending); + user = __task_cred(t)->user; + sigpending = atomic_inc_return(&user->sigpending); + if (sigpending == 1) + get_uid(user); rcu_read_unlock(); - if (override_rlimit || - atomic_read(&user->sigpending) <= - task_rlimit(t, RLIMIT_SIGPENDING)) { + if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) { q = kmem_cache_alloc(sigqueue_cachep, flags); } else { print_dropped_signal(sig); } if (unlikely(q == NULL)) { - atomic_dec(&user->sigpending); - free_uid(user); + if (atomic_dec_and_test(&user->sigpending)) + free_uid(user); } else { INIT_LIST_HEAD(&q->list); q->flags = 0; @@ -407,8 +412,8 @@ static void __sigqueue_free(struct sigqueue *q) { if (q->flags & SIGQUEUE_PREALLOC) return; - atomic_dec(&q->user->sigpending); - free_uid(q->user); + if (atomic_dec_and_test(&q->user->sigpending)) + free_uid(q->user); kmem_cache_free(sigqueue_cachep, q); } |