Hi Naota,
What happens if btrfs_bio_alloc() in submit_extent_page fails? Then we
return -ENOMEM to the caller, but we do not set *bio_ret to NULL. And
if *bio_ret was non-NULL upon entry into submit_extent_page, then we
had submitted this bio before getting to btrfs_bio_alloc(). So should
btrfs_bio_alloc() failure be handled in the same way?
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 3915c94..cd443bc 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2834,8 +2834,11 @@ static int submit_extent_page(int rw, struct
extent_io_tree *tree,
bio = btrfs_bio_alloc(bdev, sector, BIO_MAX_PAGES,
GFP_NOFS | __GFP_HIGH);
- if (!bio)
+ if (!bio) {
+ if (bio_ret)
+ *bio_ret = NULL;
return -ENOMEM;
+ }
bio_add_page(bio, page, page_size, offset);
bio->bi_end_io = end_io_func;
Thanks,
Alex.
On Wed, Jan 7, 2015 at 12:46 AM, Satoru Takeuchi
<takeuchi_sat...@jp.fujitsu.com> wrote:
> Hi Naota,
>
> On 2015/01/06 1:01, Naohiro Aota wrote:
>> After submit_one_bio(), `bio' can go away. However submit_extent_page()
>> leave `bio' referable if submit_one_bio() failed (e.g. -ENOMEM on OOM).
>> It will cause invalid paging request when submit_extent_page() is called
>> next time.
>>
>> I reproduced ENOMEM case with the following script (need
>> CONFIG_FAIL_PAGE_ALLOC, and CONFIG_FAULT_INJECTION_DEBUG_FS).
>
> I confirmed that this problem reproduce with 3.19-rc3 and
> not reproduce with 3.19-rc3 with your patch.
>
> Tested-by: Satoru Takeuchi <takeuchi_sat...@jp.fujitsu.com>
>
> Thank you for reporting this problem with the reproducer
> and fixing it too.
>
> NOTE:
> I used v3.19-rc3's tools/testing/fault-injection/failcmd.sh
> for the following "./failcmd.sh".
>
> > ./failcmd.sh -p $percent -t $times -i $interval \
> > --ignore-gfp-highmem=N --ignore-gfp-wait=N
> --min-order=0 \
> > -- \
> > cat $directory/file > /dev/null
>
> * 3.19-rc1 + your patch
>
> ===============================================================================
> # ./run
> 512+0 records in
> 512+0 records out
> #
> ===============================================================================
>
> * 3.19-rc3
>
> ===============================================================================
> # ./run
> 512+0 records in
> 512+0 records out
> [ 188.433726] run (776): drop_caches: 1
> [ 188.682372] FAULT_INJECTION: forcing a failure.
> name fail_page_alloc, interval 100, probability 111000, space 0, times 3
> [ 188.689986] CPU: 0 PID: 954 Comm: cat Not tainted 3.19.0-rc3-ktest #1
> [ 188.693834] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> Bochs 01/01/2011
> [ 188.698466] 0000000000000064 ffff88007b343618 ffffffff816e5563
> ffff88007fc0fc78
> [ 188.702730] ffffffff81c655c0 ffff88007b343638 ffffffff813851b5
> 0000000000000010
> [ 188.707043] 0000000000000002 ffff88007b343768 ffffffff81188126
> ffff88007b3435a8
> [ 188.711283] Call Trace:
> [ 188.712620] [<ffffffff816e5563>] dump_stack+0x45/0x57
> [ 188.715330] [<ffffffff813851b5>] should_fail+0x135/0x140
> [ 188.718218] [<ffffffff81188126>] __alloc_pages_nodemask+0xd6/0xb30
> [ 188.721567] [<ffffffff81339075>] ? blk_rq_map_sg+0x35/0x170
> [ 188.724558] [<ffffffffa0010705>] ? virtio_queue_rq+0x145/0x2b0
> [virtio_blk]
> [ 188.728191] [<ffffffffa01bd00f>] ?
> btrfs_submit_compressed_read+0xcf/0x4d0 [btrfs]
> [ 188.732079] [<ffffffff811d99fb>] ? kmem_cache_alloc+0x1cb/0x230
> [ 188.735153] [<ffffffff81181265>] ? mempool_alloc_slab+0x15/0x20
> [ 188.738188] [<ffffffff811cee1a>] alloc_pages_current+0x9a/0x120
> [ 188.741153] [<ffffffffa01bd0e9>] btrfs_submit_compressed_read+0x1a9/0x4d0
> [btrfs]
> [ 188.744835] [<ffffffffa0178621>] btrfs_submit_bio_hook+0x1c1/0x1d0 [btrfs]
> [ 188.748225] [<ffffffffa018b7b3>] ? lookup_extent_mapping+0x13/0x20 [btrfs]
> [ 188.751547] [<ffffffffa0179c08>] ? btrfs_get_extent+0x98/0xad0 [btrfs]
> [ 188.754656] [<ffffffffa01901d7>] submit_one_bio+0x67/0xa0 [btrfs]
> [ 188.757554] [<ffffffffa0193f27>] submit_extent_page.isra.35+0xd7/0x1c0
> [btrfs]
> [ 188.760981] [<ffffffffa019509d>] __do_readpage+0x31d/0x7b0 [btrfs]
> [ 188.763920] [<ffffffffa0195f10>] ? btrfs_create_repair_bio+0x110/0x110
> [btrfs]
> [ 188.767382] [<ffffffffa0179b70>] ? btrfs_submit_direct+0x7b0/0x7b0 [btrfs]
> [ 188.770671] [<ffffffffa018f88d>] ? btrfs_lookup_ordered_range+0x13d/0x180
> [btrfs]
> [ 188.774366] [<ffffffffa01958ca>]
> __extent_readpages.constprop.42+0x2ba/0x2d0 [btrfs]
> [ 188.778031] [<ffffffffa0179b70>] ? btrfs_submit_direct+0x7b0/0x7b0 [btrfs]
> [ 188.781241] [<ffffffffa01969b9>] extent_readpages+0x169/0x1b0 [btrfs]
> [ 188.784322] [<ffffffffa0179b70>] ? btrfs_submit_direct+0x7b0/0x7b0 [btrfs]
> [ 188.789014] [<ffffffffa0176b0f>] btrfs_readpages+0x1f/0x30 [btrfs]
> [ 188.792028] [<ffffffff8118bf5c>] __do_page_cache_readahead+0x18c/0x1f0
> [ 188.795078] [<ffffffff8118c09f>] ondemand_readahead+0xdf/0x260
> [ 188.797702] [<ffffffffa016c5df>] ? btrfs_congested_fn+0x5f/0xa0 [btrfs]
> [ 188.800718] [<ffffffff8118c291>] page_cache_async_readahead+0x71/0xa0
> [ 188.803650] [<ffffffff8118017f>] generic_file_read_iter+0x40f/0x5e0
> [ 188.806480] [<ffffffff811f43be>] new_sync_read+0x7e/0xb0
> [ 188.808832] [<ffffffff811f55d8>] __vfs_read+0x18/0x50
> [ 188.811068] [<ffffffff811f569a>] vfs_read+0x8a/0x140
> [ 188.813298] [<ffffffff811f5796>] SyS_read+0x46/0xb0
> [ 188.815486] [<ffffffff81125806>] ? __audit_syscall_exit+0x1f6/0x2a0
> [ 188.818293] [<ffffffff816eb8e9>] system_call_fastpath+0x12/0x17
> [ 188.821005] BUG: unable to handle kernel paging request at 000000010000000c
> [ 188.821984] IP: [<ffffffffa01901b3>] submit_one_bio+0x43/0xa0 [btrfs]
> [ 188.821984] PGD 7bad3067 PUD 0
> [ 188.821984] Oops: 0000 [#1] SMP
> [ 188.821984] Modules linked in: ip6table_filter ip6_tables ebtable_nat
> ebtables bnep bluetooth rfkill btrfs xor raid6_pq microcode 8139too serio_raw
> virtio_balloon 8139cp mii nfsd auth_rpcgss nfs_acl lockd grace sunrpc
> virtio_blk ata_generic pata_acpi
> [ 188.821984] CPU: 1 PID: 954 Comm: cat Not tainted 3.19.0-rc3-ktest #1
> [ 188.821984] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> Bochs 01/01/2011
> [ 188.821984] task: ffff880037665220 ti: ffff88007b340000 task.ti:
> ffff88007b340000
> [ 188.821984] RIP: 0010:[<ffffffffa01901b3>] [<ffffffffa01901b3>]
> submit_one_bio+0x43/0xa0 [btrfs]
> [ 188.821984] RSP: 0018:ffff88007b3438c8 EFLAGS: 00010202
> [ 188.821984] RAX: 0000000000000000 RBX: ffff88007c282ba8 RCX:
> 0000000000010001
> [ 188.821984] RDX: 0000000000000000 RSI: 00000000fffffff4 RDI:
> 0000000000000000
> [ 188.821984] RBP: ffff88007b3438d8 R08: ffffea0001e33100 R09:
> 00000000000027df
> [ 188.821984] R10: ffff88007fd1c000 R11: 0000000000dbb000 R12:
> ffff88007b343b40
> [ 188.821984] R13: ffff88007c282ba8 R14: 0000000000006dd8 R15:
> ffff880071584f80
> [ 188.821984] FS: 00007fdf777c5740(0000) GS:ffff88007fd00000(0000)
> knlGS:0000000000000000
> [ 188.821984] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> [ 188.821984] CR2: 000000010000000c CR3: 000000007bf59000 CR4:
> 00000000000006e0
> [ 188.821984] Stack:
> [ 188.821984] 0000000000001000 ffff88007b343b40 ffff88007b343938
> ffffffffa0193f27
> [ 188.821984] ffff88007b343938 0000000000000001 0000000000000000
> ffffea0001e33180
> [ 188.821984] 00000000027e0000 0000000000001000 ffff88007cc24680
> ffff88007b343b50
> [ 188.821984] Call Trace:
> [ 188.821984] [<ffffffffa0193f27>] submit_extent_page.isra.35+0xd7/0x1c0
> [btrfs]
> [ 188.821984] [<ffffffffa019509d>] __do_readpage+0x31d/0x7b0 [btrfs]
> [ 188.821984] [<ffffffffa0195f10>] ? btrfs_create_repair_bio+0x110/0x110
> [btrfs]
> [ 188.821984] [<ffffffffa0179b70>] ? btrfs_submit_direct+0x7b0/0x7b0 [btrfs]
> [ 188.821984] [<ffffffffa018f88d>] ? btrfs_lookup_ordered_range+0x13d/0x180
> [btrfs]
> [ 188.821984] [<ffffffffa01958ca>]
> __extent_readpages.constprop.42+0x2ba/0x2d0 [btrfs]
> [ 188.821984] [<ffffffffa0179b70>] ? btrfs_submit_direct+0x7b0/0x7b0 [btrfs]
> [ 188.821984] [<ffffffffa01969b9>] extent_readpages+0x169/0x1b0 [btrfs]
> [ 188.821984] [<ffffffffa0179b70>] ? btrfs_submit_direct+0x7b0/0x7b0 [btrfs]
> [ 188.821984] [<ffffffffa0176b0f>] btrfs_readpages+0x1f/0x30 [btrfs]
> [ 188.821984] [<ffffffff8118bf5c>] __do_page_cache_readahead+0x18c/0x1f0
> [ 188.821984] [<ffffffff8118c09f>] ondemand_readahead+0xdf/0x260
> [ 188.821984] [<ffffffffa016c5df>] ? btrfs_congested_fn+0x5f/0xa0 [btrfs]
> [ 188.821984] [<ffffffff8118c291>] page_cache_async_readahead+0x71/0xa0
> [ 188.821984] [<ffffffff8118017f>] generic_file_read_iter+0x40f/0x5e0
> [ 188.821984] [<ffffffff811f43be>] new_sync_read+0x7e/0xb0
> [ 188.821984] [<ffffffff811f55d8>] __vfs_read+0x18/0x50
> [ 188.821984] [<ffffffff811f569a>] vfs_read+0x8a/0x140
> [ 188.821984] [<ffffffff811f5796>] SyS_read+0x46/0xb0
> [ 188.821984] [<ffffffff81125806>] ? __audit_syscall_exit+0x1f6/0x2a0
> [ 188.821984] [<ffffffff816eb8e9>] system_call_fastpath+0x12/0x17
> [ 188.821984] Code: c1 e0 04 48 8d 44 06 f0 48 8b 73 50 4c 8b 00 8b 40 0c 4d
> 8b 48 10 48 c7 43 50 00 00 00 00 f0 ff 43 74 48 8b 76 20 48 85 f6 74 4d <4c>
> 8b 56 18 4d 85 d2 74 44 4d 8b 58 08 49 c1 e1 0c 49 89 c8 89
> [ 188.821984] RIP [<ffffffffa01901b3>] submit_one_bio+0x43/0xa0 [btrfs]
> [ 188.821984] RSP <ffff88007b3438c8>
> [ 188.821984] CR2: 000000010000000c
> [ 188.953169] ---[ end trace 498f24be78e8baad ]---
> #
> ===============================================================================
>
> Thanks,
> Satoru
>
>>
>> #!/bin/bash
>>
>> dmesgout=dmesg.txt
>> start=100000
>> end=300000
>> step=1000
>>
>> # btrfs options
>> device=/dev/vdb1
>> directory=/mnt/btrfs
>>
>> # fault-injection options
>> percent=100
>> times=3
>>
>> mkdir -p $directory || exit 1
>> mount -o compress $device $directory || exit 1
>>
>> rm -f $directory/file || exit 1
>> dd if=/dev/zero of=$directory/file bs=1M count=512 || exit 1
>>
>> for interval in `seq $start $step $end`; do
>> dmesg -C
>> echo 1 > /proc/sys/vm/drop_caches
>> sync
>> export FAILCMD_TYPE=fail_page_alloc
>> ./failcmd.sh -p $percent -t $times -i $interval \
>> --ignore-gfp-highmem=N --ignore-gfp-wait=N --min-order=0 \
>> -- \
>> cat $directory/file > /dev/null
>> dmesg > ${dmesgout}
>> if grep -q BUG: ${dmesgout}; then
>> cat ${dmesgout}
>> exit 1
>> fi
>> done
>>
>> umount $directory
>> exit 0
>>
>> Signed-off-by: Naohiro Aota <na...@elisp.net>
>> ---
>> fs/btrfs/extent_io.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
>> index 4ebabd2..4421161 100644
>> --- a/fs/btrfs/extent_io.c
>> +++ b/fs/btrfs/extent_io.c
>> @@ -2816,8 +2816,10 @@ static int submit_extent_page(int rw, struct
>> extent_io_tree *tree,
>> bio_add_page(bio, page, page_size, offset) < page_size) {
>> ret = submit_one_bio(rw, bio, mirror_num,
>> prev_bio_flags);
>> - if (ret < 0)
>> + if (ret < 0) {
>> + *bio_ret = NULL;
>> return ret;
>> + }
>> bio = NULL;
>> } else {
>> return 0;
>>
>
> --
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