From: Guoqing Jiang <jgq516@gmail.com>
To: song@kernel.org
Cc: linux-raid@vger.kernel.org, linux-block@vger.kernel.org,
pawel.wiejacha@rtbhouse.com,
Guoqing Jiang <jiangguoqing@kylinos.cn>
Subject: [PATCH] md: don't account io stat for split bio
Date: Sat, 8 May 2021 11:48:15 +0800 [thread overview]
Message-ID: <20210508034815.123565-1-jgq516@gmail.com> (raw)
From: Guoqing Jiang <jiangguoqing@kylinos.cn>
We have used generic io accounting functions to manage md io stats,
then for split bio, md also change it's bi_private and bi_end_io,
which could trigger double fault problem.
1146 <0>[33685.629591] traps: PANIC: double fault, error_code: 0x0
1147 <4>[33685.629593] double fault: 0000 [#1] SMP NOPTI
1148 <4>[33685.629594] CPU: 10 PID: 2118287 Comm: kworker/10:0
Tainted: P OE 5.11.8-051108-generic #202103200636
1149 <4>[33685.629595] Hardware name: ASUSTeK COMPUTER INC. KRPG-U8
Series/KRPG-U8 Series, BIOS 4201 09/25/2020
1150 <4>[33685.629595] Workqueue: xfs-conv/md12 xfs_end_io [xfs]
1151 <4>[33685.629596] RIP: 0010:__slab_free+0x23/0x340
1152 <4>[33685.629597] Code: 4c fe ff ff 0f 1f 00 0f 1f 44 00 00 55
48 89 e5 41 57 49 89 cf 41 56 49 89 fe 41 55 41 54 49 89 f4 53 48 83
e4 f0 48 83 ec 70 <48> 89 54 24 28 0f 1f 44 00 00 41 8b 46 28 4d 8b 6c
24 20 49 8b 5c
1153 <4>[33685.629598] RSP: 0018:ffffa9bc00848fa0 EFLAGS: 00010086
1154 <4>[33685.629599] RAX: ffff94c04d8b10a0 RBX: ffff94437a34a880
RCX: ffff94437a34a880
1155 <4>[33685.629599] RDX: ffff94437a34a880 RSI: ffffcec745e8d280
RDI: ffff944300043b00
1156 <4>[33685.629599] RBP: ffffa9bc00849040 R08: 0000000000000001
R09: ffffffff82a5d6de
1157 <4>[33685.629600] R10: 0000000000000001 R11: 000000009c109000
R12: ffffcec745e8d280
1158 <4>[33685.629600] R13: ffff944300043b00 R14: ffff944300043b00
R15: ffff94437a34a880
1159 <4>[33685.629601] FS: 0000000000000000(0000)
GS:ffff94c04d880000(0000) knlGS:0000000000000000
1160 <4>[33685.629601] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
1161 <4>[33685.629602] CR2: ffffa9bc00848f98 CR3: 000000014d04e000
CR4: 0000000000350ee0
1162 <4>[33685.629602] Call Trace:
1163 <4>[33685.629603] <IRQ>
1164 <4>[33685.629603] ? kfree+0x3bc/0x3e0
1165 <4>[33685.629603] ? mempool_kfree+0xe/0x10
1166 <4>[33685.629603] ? mempool_kfree+0xe/0x10
1167 <4>[33685.629604] ? mempool_free+0x2f/0x80
1168 <4>[33685.629604] ? md_end_io+0x4a/0x70
1169 <4>[33685.629604] ? bio_endio+0xdc/0x130
1170 <4>[33685.629605] ? bio_chain_endio+0x2d/0x40
1171 <4>[33685.629605] ? md_end_io+0x5c/0x70
1172 <4>[33685.629605] ? bio_endio+0xdc/0x130
1173 <4>[33685.629605] ? bio_chain_endio+0x2d/0x40
1174 <4>[33685.629606] ? md_end_io+0x5c/0x70
1175 <4>[33685.629606] ? bio_endio+0xdc/0x130
1176 <4>[33685.629606] ? bio_chain_endio+0x2d/0x40
1177 <4>[33685.629607] ? md_end_io+0x5c/0x70
... repeated ...
1436 <4>[33685.629677] ? bio_endio+0xdc/0x130
1437 <4>[33685.629677] ? bio_chain_endio+0x2d/0x40
1438 <4>[33685.629677] ? md_end_io+0x5c/0x70
1439 <4>[33685.629677] ? bio_endio+0xdc/0x130
1440 <4>[33685.629678] ? bio_chain_endio+0x2d/0x40
1441 <4>[33685.629678] ? md_
1442 <4>[33685.629679] Lost 357 message(s)!
It looks like stack overflow happened for split bio, to fix this,
let's keep split bio untouched in md_submit_bio.
As a side effect, we need to export bio_chain_endio.
[1]. https://lore.kernel.org/linux-raid/3bf04253-3fad-434a-63a7-20214e38cf26@gmail.com/T/#t
Reported-by: Paweł Wiejacha <pawel.wiejacha@rtbhouse.com>
Tested-by: Paweł Wiejacha <pawel.wiejacha@rtbhouse.com>
Fixes: 41d2d848e5c0 ("md: improve io stats accounting")
Signed-off-by: Guoqing Jiang <jiangguoqing@kylinos.cn>
---
block/bio.c | 3 ++-
drivers/md/md.c | 2 +-
include/linux/bio.h | 1 +
3 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 44205dfb6b60..759da1f6ab61 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -283,10 +283,11 @@ static struct bio *__bio_chain_endio(struct bio *bio)
return parent;
}
-static void bio_chain_endio(struct bio *bio)
+void bio_chain_endio(struct bio *bio)
{
bio_endio(__bio_chain_endio(bio));
}
+EXPORT_SYMBOL(bio_chain_endio);
/**
* bio_chain - chain bio completions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 49f897fbb89b..02fd272ff6f7 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -489,7 +489,7 @@ static blk_qc_t md_submit_bio(struct bio *bio)
return BLK_QC_T_NONE;
}
- if (bio->bi_end_io != md_end_io) {
+ if (bio->bi_end_io != md_end_io && bio->bi_end_io != bio_chain_endio) {
struct md_io *md_io;
md_io = mempool_alloc(&mddev->md_io_pool, GFP_NOIO);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index a0b4cfdf62a4..6ea48fa1ad64 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -465,6 +465,7 @@ extern void bio_init(struct bio *bio, struct bio_vec *table,
extern void bio_uninit(struct bio *);
extern void bio_reset(struct bio *);
void bio_chain(struct bio *, struct bio *);
+extern void bio_chain_endio(struct bio *bio);
extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
--
2.25.1
next reply other threads:[~2021-05-08 3:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-08 3:48 Guoqing Jiang [this message]
2021-05-10 6:00 ` [PATCH] md: don't account io stat for split bio Christoph Hellwig
2021-05-10 7:46 ` Guoqing Jiang
2021-05-10 19:49 ` Artur Paszkiewicz
2021-05-11 2:13 ` Guoqing Jiang
2021-05-11 4:38 ` Christoph Hellwig
2021-05-11 6:59 ` Song Liu
2021-05-11 7:11 ` Christoph Hellwig
2021-05-11 6:58 ` Song Liu
2021-05-11 7:10 ` Christoph Hellwig
2021-05-13 7:24 ` Guoqing Jiang
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