On 2021/4/10 上午5:40, Paweł Wiejacha wrote:
Hello,
Two of my machines constantly crash with a double fault like this:
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)!
This happens on:
5.11.8-051108-generic #202103200636 SMP Sat Mar 20 11:17:32 UTC 2021
and on 5.8.0-44-generic #50~20.04.1-Ubuntu
(https://changelogs.ubuntu.com/changelogs/pool/main/l/linux/linux_5.8.0-44.50/changelog)
which contains backported
https://github.com/torvalds/linux/commit/41d2d848e5c09209bdb57ff9c0ca34075e22783d
("md: improve io stats accounting").
The 5.8.18-050818-generic #202011011237 SMP Sun Nov 1 12:40:15 UTC
2020 which does not contain above suspected change does not crash.
If there's a better way/place to report this bug just let me know. If
not, here are steps to reproduce:
1. Create a RAID 0 device using three Micron_9300_MTFDHAL7T6TDP disks.
mdadm --create --verbose /dev/md12 --level=stripe --raid-devices=3
/dev/nvme0n1p1 /dev/nvme1n1p1 /dev/nvme2n1p1
2. Setup xfs on it:
mkfs.xfs /dev/md12 and mount it
3. Write to a file on this filesystem:
while true; do rm -rf /mnt/md12/crash* ; for i in `seq 8`; do dd
if=/dev/zero of=/mnt/md12/crash$i bs=32K count=50000000 & done; wait;
done
Wait for a crash (usually less than 20 min).
I couldn't reproduce it with a single dd process (maybe I have to wait
a little longer), but a single cat
/very/large/file/on/cephfs/over100GbE > /mnt/md12/crash is enough for
this double fault to occur.
I guess it is related with bio split, if raid0_make_request calls
bio_chain for the split bio, then
it's bi_end_io is changed to bio_chain_endio. Could you try this?
--- 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) {
If the above works, then we could miss the statistics of split bio from
blk_queue_split which is
called before hijack bi_end_io, so we may need to move blk_queue_split
after hijack bi_end_io.
Thanks,
Guoqing
