From: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp
[ Upstream commit 8b64d420fe2450f82848178506d3e3a0bd195539 ]
syzbot is reporting false a positive ODEBUG message immediately after ODEBUG was disabled due to OOM.
[ 1062.309646][T22911] ODEBUG: Out of memory. ODEBUG disabled [ 1062.886755][ T5171] ------------[ cut here ]------------ [ 1062.892770][ T5171] ODEBUG: assert_init not available (active state 0) object: ffffc900056afb20 object type: timer_list hint: process_timeout+0x0/0x40
CPU 0 [ T5171] CPU 1 [T22911] -------------- -------------- debug_object_assert_init() { if (!debug_objects_enabled) return; db = get_bucket(addr); lookup_object_or_alloc() { debug_objects_enabled = 0; return NULL; } debug_objects_oom() { pr_warn("Out of memory. ODEBUG disabled\n"); // all buckets get emptied here, and } lookup_object_or_alloc(addr, db, descr, false, true) { // this bucket is already empty. return ERR_PTR(-ENOENT); } // Emits false positive warning. debug_print_object(&o, "assert_init"); }
Recheck debug_object_enabled in debug_print_object() to avoid that.
Reported-by: syzbot syzbot+7937ba6a50bdd00fffdf@syzkaller.appspotmail.com Suggested-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Thomas Gleixner tglx@linutronix.de Link: https://lore.kernel.org/r/492fe2ae-5141-d548-ebd5-62f5fe2e57f7@I-love.SAKURA... Closes: https://syzkaller.appspot.com/bug?extid=7937ba6a50bdd00fffdf Signed-off-by: Sasha Levin sashal@kernel.org --- lib/debugobjects.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/lib/debugobjects.c b/lib/debugobjects.c index bacb00a9cd9f9..b6217c797554b 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -280,6 +280,15 @@ static void debug_print_object(struct debug_obj *obj, char *msg) struct debug_obj_descr *descr = obj->descr; static int limit;
+ /* + * Don't report if lookup_object_or_alloc() by the current thread + * failed because lookup_object_or_alloc()/debug_objects_oom() by a + * concurrent thread turned off debug_objects_enabled and cleared + * the hash buckets. + */ + if (!debug_objects_enabled) + return; + if (limit < 5 && descr != descr_test) { void *hint = descr->debug_hint ? descr->debug_hint(obj->object) : NULL;
From: Zhong Jinghua zhongjinghua@huawei.com
[ Upstream commit f12bc113ce904777fd6ca003b473b427782b3dde ]
If the index allocated by idr_alloc greater than MINORMASK >> part_shift, the device number will overflow, resulting in failure to create a block device.
Fix it by imiting the size of the max allocation.
Signed-off-by: Zhong Jinghua zhongjinghua@huawei.com Reviewed-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20230605122159.2134384-1-zhongjinghua@huaweicloud.... Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/nbd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index eb2ca7f6ab3ab..33ad48719c124 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1630,7 +1630,8 @@ static int nbd_dev_add(int index) if (err == -ENOSPC) err = -EEXIST; } else { - err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL); + err = idr_alloc(&nbd_index_idr, nbd, 0, + (MINORMASK >> part_shift) + 1, GFP_KERNEL); if (err >= 0) index = err; }
From: Yu Kuai yukuai3@huawei.com
[ Upstream commit 873f50ece41aad5c4f788a340960c53774b5526e ]
Currently, if reshape is interrupted, echo "reshape" to sync_action will restart reshape from scratch, for example:
echo frozen > sync_action echo reshape > sync_action
This will corrupt data before reshape_position if the array is growing, fix the problem by continue reshape from reshape_position.
Reported-by: Peter Neuwirth reddunur@online.de Link: https://lore.kernel.org/linux-raid/e2f96772-bfbc-f43b-6da1-f520e5164536@onli... Signed-off-by: Yu Kuai yukuai3@huawei.com Signed-off-by: Song Liu song@kernel.org Link: https://lore.kernel.org/r/20230512015610.821290-3-yukuai1@huaweicloud.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/md.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c index 69d1501d9160e..3b9cfeda02993 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -4612,11 +4612,21 @@ action_store(struct mddev *mddev, const char *page, size_t len) return -EINVAL; err = mddev_lock(mddev); if (!err) { - if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) + if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) { err = -EBUSY; - else { + } else if (mddev->reshape_position == MaxSector || + mddev->pers->check_reshape == NULL || + mddev->pers->check_reshape(mddev)) { clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); err = mddev->pers->start_reshape(mddev); + } else { + /* + * If reshape is still in progress, and + * md_check_recovery() can continue to reshape, + * don't restart reshape because data can be + * corrupted for raid456. + */ + clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); } mddev_unlock(mddev); }
From: Yu Kuai yukuai3@huawei.com
[ Upstream commit 010444623e7f4da6b4a4dd603a7da7469981e293 ]
Currently, there is no limit for raid1/raid10 plugged bio. While flushing writes, raid1 has cond_resched() while raid10 doesn't, and too many writes can cause soft lockup.
Follow up soft lockup can be triggered easily with writeback test for raid10 with ramdisks:
watchdog: BUG: soft lockup - CPU#10 stuck for 27s! [md0_raid10:1293] Call Trace: <TASK> call_rcu+0x16/0x20 put_object+0x41/0x80 __delete_object+0x50/0x90 delete_object_full+0x2b/0x40 kmemleak_free+0x46/0xa0 slab_free_freelist_hook.constprop.0+0xed/0x1a0 kmem_cache_free+0xfd/0x300 mempool_free_slab+0x1f/0x30 mempool_free+0x3a/0x100 bio_free+0x59/0x80 bio_put+0xcf/0x2c0 free_r10bio+0xbf/0xf0 raid_end_bio_io+0x78/0xb0 one_write_done+0x8a/0xa0 raid10_end_write_request+0x1b4/0x430 bio_endio+0x175/0x320 brd_submit_bio+0x3b9/0x9b7 [brd] __submit_bio+0x69/0xe0 submit_bio_noacct_nocheck+0x1e6/0x5a0 submit_bio_noacct+0x38c/0x7e0 flush_pending_writes+0xf0/0x240 raid10d+0xac/0x1ed0
Fix the problem by adding cond_resched() to raid10 like what raid1 did.
Note that unlimited plugged bio still need to be optimized, for example, in the case of lots of dirty pages writeback, this will take lots of memory and io will spend a long time in plug, hence io latency is bad.
Signed-off-by: Yu Kuai yukuai3@huawei.com Signed-off-by: Song Liu song@kernel.org Link: https://lore.kernel.org/r/20230529131106.2123367-2-yukuai1@huaweicloud.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/raid10.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 95c3a21cd7335..f2dbc1554328a 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -916,6 +916,7 @@ static void flush_pending_writes(struct r10conf *conf) else generic_make_request(bio); bio = next; + cond_resched(); } blk_finish_plug(&plug); } else @@ -1101,6 +1102,7 @@ static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule) else generic_make_request(bio); bio = next; + cond_resched(); } kfree(plug); }
From: Thomas Gleixner tglx@linutronix.de
[ Upstream commit 8ce8849dd1e78dadcee0ec9acbd259d239b7069f ]
posix_timer_add() tries to allocate a posix timer ID by starting from the cached ID which was stored by the last successful allocation.
This is done in a loop searching the ID space for a free slot one by one. The loop has to terminate when the search wrapped around to the starting point.
But that's racy vs. establishing the starting point. That is read out lockless, which leads to the following problem:
CPU0 CPU1 posix_timer_add() start = sig->posix_timer_id; lock(hash_lock); ... posix_timer_add() if (++sig->posix_timer_id < 0) start = sig->posix_timer_id; sig->posix_timer_id = 0;
So CPU1 can observe a negative start value, i.e. -1, and the loop break never happens because the condition can never be true:
if (sig->posix_timer_id == start) break;
While this is unlikely to ever turn into an endless loop as the ID space is huge (INT_MAX), the racy read of the start value caught the attention of KCSAN and Dmitry unearthed that incorrectness.
Rewrite it so that all id operations are under the hash lock.
Reported-by: syzbot+5c54bd3eb218bb595aa9@syzkaller.appspotmail.com Reported-by: Dmitry Vyukov dvyukov@google.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Frederic Weisbecker frederic@kernel.org Link: https://lore.kernel.org/r/87bkhzdn6g.ffs@tglx Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/sched/signal.h | 2 +- kernel/time/posix-timers.c | 31 ++++++++++++++++++------------- 2 files changed, 19 insertions(+), 14 deletions(-)
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index bcaba7e8ca6ea..916f4807cc9a6 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -119,7 +119,7 @@ struct signal_struct { #ifdef CONFIG_POSIX_TIMERS
/* POSIX.1b Interval Timers */ - int posix_timer_id; + unsigned int next_posix_timer_id; struct list_head posix_timers;
/* ITIMER_REAL timer for the process */ diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c index 8b90abd690730..309c551ac18fd 100644 --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -168,25 +168,30 @@ 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; - int ret = -ENOENT; + unsigned int cnt, id;
- do { + /* + * 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++) { spin_lock(&hash_lock); - head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)]; - if (!__posix_timers_find(head, sig, sig->posix_timer_id)) { + 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)) { hlist_add_head_rcu(&timer->t_hash, head); - ret = sig->posix_timer_id; + spin_unlock(&hash_lock); + return 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); - } while (ret == -ENOENT); - return ret; + } + /* POSIX return code when no timer ID could be allocated */ + return -EAGAIN; }
static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
linux-stable-mirror@lists.linaro.org
-
Sasha Levin