| Message ID | CAOcd+r10Q08zhvjMawOrQ8jWBReD6dYxeEtiZSoqUEuHCeM27g@mail.gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On 10/11/15 20:09, Alex Lyakas wrote: > 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; > Did you get any feedback on this? It seems it could cause data loss or corruption on allocation failures, no? -h -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Holger, I think it will cause an invalid paging request, just like in case that Naohiro has fixed. I am not running the "latest and greatest" btrfs in my system, and it is not easy to set it up, that's why I cannot submit patches based on the latest code, I can only review and comment on patches. Alex. On Thu, Nov 5, 2015 at 3:08 PM, Holger Hoffstätte <holger.hoffstaette@googlemail.com> wrote: > On 10/11/15 20:09, Alex Lyakas wrote: >> 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; >> > > Did you get any feedback on this? It seems it could cause data loss or > corruption on allocation failures, no? > > -h > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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);
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? bio->bi_end_io = end_io_func; Thanks, Alex. On Wed, Jan 7, 2015 at 12:46 AM, Satoru Takeuchi <takeuchi_satoru@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_satoru@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 <naota@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; >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html