lisa/android_kernel_xiaomi_sm8350
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Revert "posix-timers: Ensure timer ID search-loop limit is valid"

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This reverts commit 8ad6679a5b which is
commit 8ce8849dd1e78dadcee0ec9acbd259d239b7069f upstream.

It breaks the Android abi.  If it is required in the future, it can come
back in an abi-safe way.

Bug: 161946584
Change-Id: I44be0f7b4df730e599bf80939b6d40d4f8d04a57
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Greg Kroah-Hartman 2023-08-04 07:11:13 +00:00
parent f829d76234
commit 7233414aeb
2 changed files with 14 additions and 19 deletions
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2
include/linux/sched/signal.h
View File

@ -124,7 +124,7 @@ struct signal_struct {
#ifdef CONFIG_POSIX_TIMERS
/* POSIX.1b Interval Timers */
unsigned int next_posix_timer_id;
int posix_timer_id;
struct list_head posix_timers;
/* ITIMER_REAL timer for the process */

31
kernel/time/posix-timers.c
View File

@ -138,30 +138,25 @@ static struct k_itimer *posix_timer_by_id(timer_t id)
static int posix_timer_add(struct k_itimer *timer)
{
struct signal_struct *sig = current->signal;
int first_free_id = sig->posix_timer_id;
struct hlist_head *head;
unsigned int cnt, id;
int ret = -ENOENT;
/*
* FIXME: Replace this by a per signal struct xarray once there is
* a plan to handle the resulting CRIU regression gracefully.
*/
for (cnt = 0; cnt <= INT_MAX; cnt++) {
do {
spin_lock(&hash_lock);
id = sig->next_posix_timer_id;
/* Write the next ID back. Clamp it to the positive space */
sig->next_posix_timer_id = (id + 1) & INT_MAX;
head = &posix_timers_hashtable[hash(sig, id)];
if (!__posix_timers_find(head, sig, id)) {
head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)];
if (!__posix_timers_find(head, sig, sig->posix_timer_id)) {
hlist_add_head_rcu(&timer->t_hash, head);
spin_unlock(&hash_lock);
return id;
ret = sig->posix_timer_id;
}
if (++sig->posix_timer_id < 0)
sig->posix_timer_id = 0;
if ((sig->posix_timer_id == first_free_id) && (ret == -ENOENT))
/* Loop over all possible ids completed */
ret = -EAGAIN;
spin_unlock(&hash_lock);
}
/* POSIX return code when no timer ID could be allocated */
return -EAGAIN;
} while (ret == -ENOENT);
return ret;
}
static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)