On Thu, Apr 22, 2021 at 7:36 PM Guoqing Jiang <jgq516@xxxxxxxxx> wrote: > > > > 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! This is likely the problem here. Pawel, please give this a try. Thanks, Song
