From: YueHaibing <yuehaibing@huawei.com>
To: <linux-ext4@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<tytso@mit.edu>, <adilger.kernel@dilger.ca>,
<riteshh@linux.ibm.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Subject: [PATCH] ext4: mballoc: Disable preemption before getting per-CPU pointer
Date: Wed, 10 Jun 2020 21:49:19 +0800 [thread overview]
Message-ID: <20200610134919.73688-1-yuehaibing@huawei.com> (raw)
BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u16:3/2181
caller is ext4_mb_new_blocks+0x388/0xed0
CPU: 2 PID: 2181 Comm: kworker/u16:3 Not tainted 5.7.0+ #182
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
dump_stack+0xb9/0xfc
debug_smp_processor_id+0xc8/0xd0
ext4_mb_new_blocks+0x388/0xed0
ext4_ext_map_blocks+0xa92/0xff0
ext4_map_blocks+0x34e/0x580
ext4_writepages+0xa28/0x11b0
do_writepages+0x46/0xe0
__writeback_single_inode+0x5f/0x6b0
writeback_sb_inodes+0x290/0x620
__writeback_inodes_wb+0x62/0xb0
wb_writeback+0x36c/0x520
wb_workfn+0x319/0x680
process_one_work+0x271/0x640
worker_thread+0x3a/0x3a0
kthread+0x14e/0x170
ret_from_fork+0x27/0x40
Disable preemption before accessing discard_pa_seq.
Fixes: 07b5b8e1ac40 ("ext4: mballoc: introduce pcpu seqcnt for freeing PA to improve ENOSPC handling")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
---
fs/ext4/mballoc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index a9083113a8c0..30b3bfb1e06a 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4708,7 +4708,8 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
}
ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
- seq = *this_cpu_ptr(&discard_pa_seq);
+ seq = *get_cpu_ptr(&discard_pa_seq);
+ put_cpu_ptr(&discard_pa_seq);
if (!ext4_mb_use_preallocated(ac)) {
ac->ac_op = EXT4_MB_HISTORY_ALLOC;
ext4_mb_normalize_request(ac, ar);
--
2.20.1
next reply other threads:[~2020-06-10 13:51 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-10 13:49 YueHaibing [this message]
2020-06-11 1:21 ` [PATCH] ext4: mballoc: Disable preemption before getting per-CPU pointer Ritesh Harjani
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