On Fri, Oct 21, 2022 at 3:50 AM Song Liu <song@xxxxxxxxxx> wrote:
>
> On Sun, Oct 16, 2022 at 7:11 PM Xiao Ni <xni@xxxxxxxxxx> wrote:
> >
> > It has added io_acct_set for raid0/raid5 io accounting and it needs to
> > alloc md_io_acct in the i/o path. They are free when the bios come back
> > from member disks. Now we don't have a method to monitor if those bios
> > are all come back. In the takeover process, it needs to free the raid0
> > memory resource including the memory pool for md_io_acct. But maybe some
> > bios are still not returned. When those bios are returned, it can cause
> > panic bcause of introducing NULL pointer or invalid address.
> >
> > This patch adds io_acct_cnt. So when stopping raid0, it can use this
> > to wait until all bios come back.
> >
> > Reported-by: Fine Fan <ffan@xxxxxxxxxx>
> > Signed-off-by: Xiao Ni <xni@xxxxxxxxxx>
>
> I have seen a lot of warnings and errors in dmesg with this patch. For example:
>
> [ 402.116463] =============================================================================
> [ 402.117176] BUG bio-144 (Tainted: G B W ): Right
> Redzone overwritten
> [ 402.117837] -----------------------------------------------------------------------------
> [ 402.117837]
> [ 402.118713] 0xffff88816f683cd0-0xffff88816f683cd7 @offset=15568.
> First byte 0x0 instead of 0xcc
> [ 402.119505] Allocated in mempool_alloc+0x79/0x1a0 age=1038 cpu=19 pid=1130
> [ 402.120133] kmem_cache_alloc+0x2dc/0x3c0
> [ 402.120510] mempool_alloc+0x79/0x1a0
> [ 402.120840] bio_alloc_bioset+0xcb/0x530
> [ 402.121205] bio_alloc_clone+0x20/0x60
> [ 402.121560] md_account_bio+0x41/0x80
> [ 402.121890] raid5_make_request+0x1cf/0x1450
> [ 402.122327] md_handle_request+0x26c/0x3f0
> [ 402.122700] __submit_bio+0x53/0x180
> [ 402.123030] submit_bio_noacct_nocheck+0xe8/0x2b0
> [ 402.123453] __blkdev_direct_IO_async+0x109/0x1d0
> [ 402.123897] generic_file_direct_write+0x9c/0x1e0
> [ 402.124332] __generic_file_write_iter+0x95/0x170
> [ 402.124771] blkdev_write_iter+0xe9/0x180
> [ 402.125162] aio_write+0x11a/0x2e0
> [ 402.125503] io_submit_one+0x627/0xd20
> [ 402.125844] __x64_sys_io_submit+0x88/0x250
> [ 402.126223] Slab 0xffffea0005bda000 objects=51 used=51
> fp=0x0000000000000000 flags=0x200000000010200(slab|head|node=0|zone=2)
> [ 402.127227] Object 0xffff88816f683c40 @offset=15424 fp=0x0000000000000000
> [ 402.127227]
> [ 402.127960] Redzone ffff88816f683c00: cc cc cc cc cc cc cc cc cc
> cc cc cc cc cc cc cc ................
> [ 402.128797] Redzone ffff88816f683c10: cc cc cc cc cc cc cc cc cc
> cc cc cc cc cc cc cc ................
> [ 402.129665] Redzone ffff88816f683c20: cc cc cc cc cc cc cc cc cc
> cc cc cc cc cc cc cc ................
> [ 402.130503] Redzone ffff88816f683c30: cc cc cc cc cc cc cc cc cc
> cc cc cc cc cc cc cc ................
> [ 402.131336] Object ffff88816f683c40: 80 a3 68 6f 81 88 ff ff af
> 21 00 00 01 00 00 00 ..ho.....!......
> [ 402.132166] Object ffff88816f683c50: 00 00 00 00 00 00 00 00 80
> 23 09 0b 81 88 ff ff .........#......
> [ 402.132996] Object ffff88816f683c60: 01 88 00 00 02 00 04 40 00
> 5a 5a 5a 00 00 00 00 .......@.ZZZ....
> [ 402.133822] Object ffff88816f683c70: 88 86 1c 00 00 00 00 00 00
> 10 00 00 00 00 00 00 ................
> [ 402.134647] Object ffff88816f683c80: 00 00 00 00 ff ff ff ff e0
> a9 a8 81 ff ff ff ff ................
> [ 402.135501] Object ffff88816f683c90: 40 3c 68 6f 81 88 ff ff 00
> 00 00 00 00 00 00 00 @<ho............
> [ 402.136354] Object ffff88816f683ca0: 00 00 00 00 00 00 00 00 00
> 00 00 00 00 00 00 00 ................
> [ 402.137174] Object ffff88816f683cb0: 00 00 00 00 00 00 00 00 00
> 00 00 00 01 00 00 00 ................
> [ 402.138027] Object ffff88816f683cc0: 00 a4 68 6f 81 88 ff ff 40
> 2f c4 73 81 88 ff ff ..ho....@/.s....
> [ 402.138857] Redzone ffff88816f683cd0: 00 20 c4 73 81 88 ff ff
> . .s....
> [ 402.139657] Padding ffff88816f683d20: 5a 5a 5a 5a 5a 5a 5a 5a 5a
> 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ
> [ 402.140510] Padding ffff88816f683d30: 5a 5a 5a 5a 5a 5a 5a 5a 5a
> 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ
> [ 402.141345] CPU: 29 PID: 1092 Comm: md0_raid5 Tainted: G B W
> 6.1.0-rc1+ #145
> [ 402.142083] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
> [ 402.143127] Call Trace:
> [ 402.143365] <TASK>
> [ 402.143563] dump_stack_lvl+0x45/0x5d
> [ 402.143899] check_bytes_and_report.cold+0x6d/0x85
> [ 402.144343] check_object+0x1fa/0x2d0
> [ 402.144675] free_debug_processing+0x1bc/0x660
> [ 402.145091] ? md_end_io_acct+0x3c/0x80
> [ 402.145464] ? md_end_io_acct+0x3c/0x80
> [ 402.145812] kmem_cache_free+0x55f/0x5b0
> [ 402.146164] md_end_io_acct+0x3c/0x80
> [ 402.146498] handle_stripe+0x11a5/0x1d70
> [ 402.146849] handle_active_stripes.constprop.0+0x487/0x5e0
> [ 402.147353] raid5d+0x40d/0x680
> [ 402.147640] ? lock_acquire+0x1ad/0x310
> [ 402.147989] md_thread+0xc2/0x170
> [ 402.148319] ? prepare_to_wait_exclusive+0xe0/0xe0
> [ 402.148749] ? register_md_personality+0x90/0x90
> [ 402.149162] kthread+0xf2/0x120
> [ 402.149455] ? kthread_complete_and_exit+0x20/0x20
> [ 402.149884] ret_from_fork+0x22/0x30
> [ 402.150211] </TASK>
> [ 402.150431] FIX bio-144: Restoring Right Redzone
> 0xffff88816f683cd0-0xffff88816f683cd7=0xcc
> [ 402.151196] FIX bio-144: Object at 0xffff88816f683c40 not freed
>
> Please fix them and resend.
>
> Thanks,
> Song
Hi Song
What commands do you run? I've run some tests and didn't see the messages.
By the way, what disks do you use?
Regards
Xiao
>
>
> > ---
> > drivers/md/md.c | 13 ++++++++++++-
> > drivers/md/md.h | 11 ++++++++---
> > drivers/md/raid0.c | 6 ++++++
> > 3 files changed, 26 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/md/md.c b/drivers/md/md.c
> > index 9dc0175280b4..57dc2ddf1e11 100644
> > --- a/drivers/md/md.c
> > +++ b/drivers/md/md.c
> > @@ -673,6 +673,7 @@ void mddev_init(struct mddev *mddev)
> > atomic_set(&mddev->flush_pending, 0);
> > init_waitqueue_head(&mddev->sb_wait);
> > init_waitqueue_head(&mddev->recovery_wait);
> > + init_waitqueue_head(&mddev->wait_io_acct);
> > mddev->reshape_position = MaxSector;
> > mddev->reshape_backwards = 0;
> > mddev->last_sync_action = "none";
> > @@ -8600,15 +8601,18 @@ int acct_bioset_init(struct mddev *mddev)
> > {
> > int err = 0;
> >
> > - if (!bioset_initialized(&mddev->io_acct_set))
> > + if (!bioset_initialized(&mddev->io_acct_set)) {
> > + atomic_set(&mddev->io_acct_cnt, 0);
> > err = bioset_init(&mddev->io_acct_set, BIO_POOL_SIZE,
> > offsetof(struct md_io_acct, bio_clone), 0);
> > + }
> > return err;
> > }
> > EXPORT_SYMBOL_GPL(acct_bioset_init);
> >
> > void acct_bioset_exit(struct mddev *mddev)
> > {
> > + WARN_ON(atomic_read(&mddev->io_acct_cnt) != 0);
> > bioset_exit(&mddev->io_acct_set);
> > }
> > EXPORT_SYMBOL_GPL(acct_bioset_exit);
> > @@ -8617,12 +8621,17 @@ static void md_end_io_acct(struct bio *bio)
> > {
> > struct md_io_acct *md_io_acct = bio->bi_private;
> > struct bio *orig_bio = md_io_acct->orig_bio;
> > + struct mddev *mddev = md_io_acct->mddev;
> >
> > orig_bio->bi_status = bio->bi_status;
> >
> > bio_end_io_acct(orig_bio, md_io_acct->start_time);
> > bio_put(bio);
> > bio_endio(orig_bio);
> > +
> > + if (atomic_dec_and_test(&mddev->io_acct_cnt))
> > + if (unlikely(test_bit(MD_QUIESCE, &mddev->flags)))
> > + wake_up(&mddev->wait_io_acct);
> > }
> >
> > /*
> > @@ -8642,6 +8651,8 @@ void md_account_bio(struct mddev *mddev, struct bio **bio)
> > md_io_acct = container_of(clone, struct md_io_acct, bio_clone);
> > md_io_acct->orig_bio = *bio;
> > md_io_acct->start_time = bio_start_io_acct(*bio);
> > + md_io_acct->mddev = mddev;
> > + atomic_inc(&mddev->io_acct_cnt);
> >
> > clone->bi_end_io = md_end_io_acct;
> > clone->bi_private = md_io_acct;
> > diff --git a/drivers/md/md.h b/drivers/md/md.h
> > index b4e2d8b87b61..061176ff325f 100644
> > --- a/drivers/md/md.h
> > +++ b/drivers/md/md.h
> > @@ -255,6 +255,7 @@ struct md_cluster_info;
> > * array is ready yet.
> > * @MD_BROKEN: This is used to stop writes and mark array as failed.
> > * @MD_DELETED: This device is being deleted
> > + * @MD_QUIESCE: This device is being quiesced. Now only raid0 use this flag
> > *
> > * change UNSUPPORTED_MDDEV_FLAGS for each array type if new flag is added
> > */
> > @@ -272,6 +273,7 @@ enum mddev_flags {
> > MD_NOT_READY,
> > MD_BROKEN,
> > MD_DELETED,
> > + MD_QUIESCE,
> > };
> >
> > enum mddev_sb_flags {
> > @@ -513,6 +515,8 @@ struct mddev {
> > * metadata and bitmap writes
> > */
> > struct bio_set io_acct_set; /* for raid0 and raid5 io accounting */
> > + atomic_t io_acct_cnt;
> > + wait_queue_head_t wait_io_acct;
> >
> > /* Generic flush handling.
> > * The last to finish preflush schedules a worker to submit
> > @@ -710,9 +714,10 @@ struct md_thread {
> > };
> >
> > struct md_io_acct {
> > - struct bio *orig_bio;
> > - unsigned long start_time;
> > - struct bio bio_clone;
> > + struct bio *orig_bio;
> > + unsigned long start_time;
> > + struct bio bio_clone;
> > + struct mddev *mddev;
> > };
> >
> > #define THREAD_WAKEUP 0
> > diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> > index 857c49399c28..aced0ad8cdab 100644
> > --- a/drivers/md/raid0.c
> > +++ b/drivers/md/raid0.c
> > @@ -754,6 +754,12 @@ static void *raid0_takeover(struct mddev *mddev)
> >
> > static void raid0_quiesce(struct mddev *mddev, int quiesce)
> > {
> > + /* It doesn't use a separate struct to count how many bios are submitted
> > + * to member disks to avoid memory alloc and performance decrease
> > + */
> > + set_bit(MD_QUIESCE, &mddev->flags);
> > + wait_event(mddev->wait_io_acct, !atomic_read(&mddev->io_acct_cnt));
> > + clear_bit(MD_QUIESCE, &mddev->flags);
> > }
> >
> > static struct md_personality raid0_personality=
> > --
> > 2.32.0 (Apple Git-132)
> >
>
