- 11 12月, 2014 3 次提交
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由 Filipe Manana 提交于
When we abort a transaction we iterate over all the ranges marked as dirty in fs_info->freed_extents[0] and fs_info->freed_extents[1], clear them from those trees, add them back (unpin) to the free space caches and, if the fs was mounted with "-o discard", perform a discard on those regions. Also, after adding the regions to the free space caches, a fitrim ioctl call can see those ranges in a block group's free space cache and perform a discard on the ranges, so the same issue can happen without "-o discard" as well. This causes corruption, affecting one or multiple btree nodes (in the worst case leaving the fs unmountable) because some of those ranges (the ones in the fs_info->pinned_extents tree) correspond to btree nodes/leafs that are referred by the last committed super block - breaking the rule that anything that was committed by a transaction is untouched until the next transaction commits successfully. I ran into this while running in a loop (for several hours) the fstest that I recently submitted: [PATCH] fstests: add btrfs test to stress chunk allocation/removal and fstrim The corruption always happened when a transaction aborted and then fsck complained like this: _check_btrfs_filesystem: filesystem on /dev/sdc is inconsistent *** fsck.btrfs output *** Check tree block failed, want=94945280, have=0 Check tree block failed, want=94945280, have=0 Check tree block failed, want=94945280, have=0 Check tree block failed, want=94945280, have=0 Check tree block failed, want=94945280, have=0 read block failed check_tree_block Couldn't open file system In this case 94945280 corresponded to the root of a tree. Using frace what I observed was the following sequence of steps happened: 1) transaction N started, fs_info->pinned_extents pointed to fs_info->freed_extents[0]; 2) node/eb 94945280 is created; 3) eb is persisted to disk; 4) transaction N commit starts, fs_info->pinned_extents now points to fs_info->freed_extents[1], and transaction N completes; 5) transaction N + 1 starts; 6) eb is COWed, and btrfs_free_tree_block() called for this eb; 7) eb range (94945280 to 94945280 + 16Kb) is added to fs_info->pinned_extents (fs_info->freed_extents[1]); 8) Something goes wrong in transaction N + 1, like hitting ENOSPC for example, and the transaction is aborted, turning the fs into readonly mode. The stack trace I got for example: [112065.253935] [<ffffffff8140c7b6>] dump_stack+0x4d/0x66 [112065.254271] [<ffffffff81042984>] warn_slowpath_common+0x7f/0x98 [112065.254567] [<ffffffffa0325990>] ? __btrfs_abort_transaction+0x50/0x10b [btrfs] [112065.261674] [<ffffffff810429e5>] warn_slowpath_fmt+0x48/0x50 [112065.261922] [<ffffffffa032949e>] ? btrfs_free_path+0x26/0x29 [btrfs] [112065.262211] [<ffffffffa0325990>] __btrfs_abort_transaction+0x50/0x10b [btrfs] [112065.262545] [<ffffffffa036b1d6>] btrfs_remove_chunk+0x537/0x58b [btrfs] [112065.262771] [<ffffffffa033840f>] btrfs_delete_unused_bgs+0x1de/0x21b [btrfs] [112065.263105] [<ffffffffa0343106>] cleaner_kthread+0x100/0x12f [btrfs] (...) [112065.264493] ---[ end trace dd7903a975a31a08 ]--- [112065.264673] BTRFS: error (device sdc) in btrfs_remove_chunk:2625: errno=-28 No space left [112065.264997] BTRFS info (device sdc): forced readonly 9) The clear kthread sees that the BTRFS_FS_STATE_ERROR bit is set in fs_info->fs_state and calls btrfs_cleanup_transaction(), which in turn calls btrfs_destroy_pinned_extent(); 10) Then btrfs_destroy_pinned_extent() iterates over all the ranges marked as dirty in fs_info->freed_extents[], and for each one it calls discard, if the fs was mounted with "-o discard", and adds the range to the free space cache of the respective block group; 11) btrfs_trim_block_group(), invoked from the fitrim ioctl code path, sees the free space entries and performs a discard; 12) After an umount and mount (or fsck), our eb's location on disk was full of zeroes, and it should have been untouched, because it was marked as dirty in the fs_info->pinned_extents tree, and therefore used by the trees that the last committed superblock points to. Fix this by not performing a discard and not adding the ranges to the free space caches - it's useless from this point since the fs is now in readonly mode and we won't write free space caches to disk anymore (otherwise we would leak space) nor any new superblock. By not adding the ranges to the free space caches, it prevents other code paths from allocating that space and write to it as well, therefore being safer and simpler. This isn't a new problem, as it's been present since 2011 (git commit acce952b). Cc: stable@vger.kernel.org # any kernel released after 2011-01-06 Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
Always clear a block group's rbnode after removing it from the rbtree to ensure that any tasks that might be holding a reference on the block group don't end up accessing stale rbnode left and right child pointers through next_block_group(). This is a leftover from the change titled: "Btrfs: fix invalid block group rbtree access after bg is removed" Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
The call to remove_extent_mapping() actually deletes the extent map from the list it's included in - fs_info->pinned_chunks - and that list is protected by the chunk mutex. Therefore make that call while holding the chunk mutex and remove the redundant list delete call because it's a noop. This fixes an overlook of the patch titled "Btrfs: fix race between fs trimming and block group remove/allocation" following the same obvervation from the patch titled "Btrfs: fix unprotected deletion from pending_chunks list". Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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- 03 12月, 2014 21 次提交
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由 Josef Bacik 提交于
This was written when we didn't do a caching control for the fast free space cache loading. However we started doing that a long time ago, and there is still a small window of time that we could be caching the block group the fast way, so if there is a caching_ctl at all on the block group just return it, the callers all wait properly for what they want. Thanks, Signed-off-by: NJosef Bacik <jbacik@fb.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
On block group remove if the corresponding extent map was on the transaction->pending_chunks list, we were deleting the extent map from that list, through remove_extent_mapping(), without any synchronization with chunk allocation (which iterates that list and adds new elements to it). Fix this by ensure that this is done while the chunk mutex is held, since that's the mutex that protects the list in the chunk allocation code path. This applies on top (depends on) of my previous patch titled: "Btrfs: fix race between fs trimming and block group remove/allocation" But the issue in fact was already present before that change, it only became easier to hit after Josef's 3.18 patch that added automatic removal of empty block groups. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
On chunk allocation error (label "error_del_extent"), after adding the extent map to the tree and to the pending chunks list, we would leave decrementing the extent map's refcount by 2 instead of 3 (our allocation + tree reference + list reference). Also, on chunk/block group removal, if the block group was on the list pending_chunks we weren't decrementing the respective list reference. Detected by 'rmmod btrfs': [20770.105881] kmem_cache_destroy btrfs_extent_map: Slab cache still has objects [20770.106127] CPU: 2 PID: 11093 Comm: rmmod Tainted: G W L 3.17.0-rc5-btrfs-next-1+ #1 [20770.106128] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [20770.106130] 0000000000000000 ffff8800ba867eb8 ffffffff813e7a13 ffff8800a2e11040 [20770.106132] ffff8800ba867ed0 ffffffff81105d0c 0000000000000000 ffff8800ba867ee0 [20770.106134] ffffffffa035d65e ffff8800ba867ef0 ffffffffa03b0654 ffff8800ba867f78 [20770.106136] Call Trace: [20770.106142] [<ffffffff813e7a13>] dump_stack+0x45/0x56 [20770.106145] [<ffffffff81105d0c>] kmem_cache_destroy+0x4b/0x90 [20770.106164] [<ffffffffa035d65e>] extent_map_exit+0x1a/0x1c [btrfs] [20770.106176] [<ffffffffa03b0654>] exit_btrfs_fs+0x27/0x9d3 [btrfs] [20770.106179] [<ffffffff8109dc97>] SyS_delete_module+0x153/0x1c4 [20770.106182] [<ffffffff8121261b>] ? trace_hardirqs_on_thunk+0x3a/0x3c [20770.106184] [<ffffffff813ebf52>] system_call_fastpath+0x16/0x1b This applies on top (depends on) of my previous patch titled: "Btrfs: fix race between fs trimming and block group remove/allocation" But the issue in fact was already present before that change, it only became easier to hit after Josef's 3.18 patch that added automatic removal of empty block groups. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
There was a free space entry structure memeory leak if a block group is remove while a free space entry is being trimmed, which the following diagram explains: CPU 1 CPU 2 btrfs_trim_block_group() trim_no_bitmap() remove free space entry from block group cache's rbtree do_trimming() btrfs_remove_block_group() btrfs_remove_free_space_cache() add back free space entry to block group's cache rbtree btrfs_put_block_group() (...) btrfs_put_block_group() kfree(bg->free_space_ctl) kfree(bg) The free space entry added after doing the discard of its respective range ends up never being freed. Detected after doing an "rmmod btrfs" after running the stress test recently submitted for fstests: [ 8234.642212] kmem_cache_destroy btrfs_free_space: Slab cache still has objects [ 8234.642657] CPU: 1 PID: 32276 Comm: rmmod Tainted: G W L 3.17.0-rc5-btrfs-next-2+ #1 [ 8234.642660] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [ 8234.642664] 0000000000000000 ffff8801af1b3eb8 ffffffff8140c7b6 ffff8801dbedd0c0 [ 8234.642670] ffff8801af1b3ed0 ffffffff811149ce 0000000000000000 ffff8801af1b3ee0 [ 8234.642676] ffffffffa042dbe7 ffff8801af1b3ef0 ffffffffa0487422 ffff8801af1b3f78 [ 8234.642682] Call Trace: [ 8234.642692] [<ffffffff8140c7b6>] dump_stack+0x4d/0x66 [ 8234.642699] [<ffffffff811149ce>] kmem_cache_destroy+0x4d/0x92 [ 8234.642731] [<ffffffffa042dbe7>] btrfs_destroy_cachep+0x63/0x76 [btrfs] [ 8234.642757] [<ffffffffa0487422>] exit_btrfs_fs+0x9/0xbe7 [btrfs] [ 8234.642762] [<ffffffff810a76a5>] SyS_delete_module+0x155/0x1c6 [ 8234.642768] [<ffffffff8122a7eb>] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 8234.642773] [<ffffffff814122d2>] system_call_fastpath+0x16/0x1b This applies on top (depends on) of my previous patch titled: "Btrfs: fix race between fs trimming and block group remove/allocation" Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
If the transaction handle doesn't have used blocks but has created new block groups make sure we turn the fs into readonly mode too. This is because the new block groups didn't get all their metadata persisted into the chunk and device trees, and therefore if a subsequent transaction starts, allocates space from the new block groups, writes data or metadata into that space, commits successfully and then after we unmount and mount the filesystem again, the same space can be allocated again for a new block group, resulting in file data or metadata corruption. Example where we don't abort the transaction when we fail to finish the chunk allocation (add items to the chunk and device trees) and later a future transaction where the block group is removed fails because it can't find the chunk item in the chunk tree: [25230.404300] WARNING: CPU: 0 PID: 7721 at fs/btrfs/super.c:260 __btrfs_abort_transaction+0x50/0xfc [btrfs]() [25230.404301] BTRFS: Transaction aborted (error -28) [25230.404302] Modules linked in: btrfs dm_flakey nls_utf8 fuse xor raid6_pq ntfs vfat msdos fat xfs crc32c_generic libcrc32c ext3 jbd ext2 dm_mod nfsd auth_rpcgss oid_registry nfs_acl nfs lockd fscache sunrpc loop psmouse i2c_piix4 i2ccore parport_pc parport processor button pcspkr serio_raw thermal_sys evdev microcode ext4 crc16 jbd2 mbcache sr_mod cdrom ata_generic sg sd_mod crc_t10dif crct10dif_generic crct10dif_common virtio_scsi floppy e1000 ata_piix libata virtio_pci virtio_ring scsi_mod virtio [last unloaded: btrfs] [25230.404325] CPU: 0 PID: 7721 Comm: xfs_io Not tainted 3.17.0-rc5-btrfs-next-1+ #1 [25230.404326] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [25230.404328] 0000000000000000 ffff88004581bb08 ffffffff813e7a13 ffff88004581bb50 [25230.404330] ffff88004581bb40 ffffffff810423aa ffffffffa049386a 00000000ffffffe4 [25230.404332] ffffffffa05214c0 000000000000240c ffff88010fc8f800 ffff88004581bba8 [25230.404334] Call Trace: [25230.404338] [<ffffffff813e7a13>] dump_stack+0x45/0x56 [25230.404342] [<ffffffff810423aa>] warn_slowpath_common+0x7f/0x98 [25230.404351] [<ffffffffa049386a>] ? __btrfs_abort_transaction+0x50/0xfc [btrfs] [25230.404353] [<ffffffff8104240b>] warn_slowpath_fmt+0x48/0x50 [25230.404362] [<ffffffffa049386a>] __btrfs_abort_transaction+0x50/0xfc [btrfs] [25230.404374] [<ffffffffa04a8c43>] btrfs_create_pending_block_groups+0x10c/0x135 [btrfs] [25230.404387] [<ffffffffa04b77fd>] __btrfs_end_transaction+0x7e/0x2de [btrfs] [25230.404398] [<ffffffffa04b7a6d>] btrfs_end_transaction+0x10/0x12 [btrfs] [25230.404408] [<ffffffffa04a3d64>] btrfs_check_data_free_space+0x111/0x1f0 [btrfs] [25230.404421] [<ffffffffa04c53bd>] __btrfs_buffered_write+0x160/0x48d [btrfs] [25230.404425] [<ffffffff811a9268>] ? cap_inode_need_killpriv+0x2d/0x37 [25230.404429] [<ffffffff810f6501>] ? get_page+0x1a/0x2b [25230.404441] [<ffffffffa04c7c95>] btrfs_file_write_iter+0x321/0x42f [btrfs] [25230.404443] [<ffffffff8110f5d9>] ? handle_mm_fault+0x7f3/0x846 [25230.404446] [<ffffffff813e98c5>] ? mutex_unlock+0x16/0x18 [25230.404449] [<ffffffff81138d68>] new_sync_write+0x7c/0xa0 [25230.404450] [<ffffffff81139401>] vfs_write+0xb0/0x112 [25230.404452] [<ffffffff81139c9d>] SyS_pwrite64+0x66/0x84 [25230.404454] [<ffffffff813ebf52>] system_call_fastpath+0x16/0x1b [25230.404455] ---[ end trace 5aa5684fdf47ab38 ]--- [25230.404458] BTRFS warning (device sdc): btrfs_create_pending_block_groups:9228: Aborting unused transaction(No space left). [25288.084814] BTRFS: error (device sdc) in btrfs_free_chunk:2509: errno=-2 No such entry (Failed lookup while freeing chunk.) Signed-off-by: NFilipe Manana <fdmanana@suse.com> Reviewed-by: NJosef Bacik <jbacik@fb.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
Trimming is completely transactionless, and the way it operates consists of hiding free space entries from a block group, perform the trim/discard and then make the free space entries visible again. Therefore while a free space entry is being trimmed, we can have free space cache writing running in parallel (as part of a transaction commit) which will miss the free space entry. This means that an unmount (or crash/reboot) after that transaction commit and mount again before another transaction starts/commits after the discard finishes, we will have some free space that won't be used again unless the free space cache is rebuilt. After the unmount, fsck (btrfsck, btrfs check) reports the issue like the following example: *** fsck.btrfs output *** checking extents checking free space cache There is no free space entry for 521764864-521781248 There is no free space entry for 521764864-1103101952 cache appears valid but isnt 29360128 Checking filesystem on /dev/sdc UUID: b4789e27-4774-4626-98e9-ae8dfbfb0fb5 found 1235681286 bytes used err is -22 (...) Another issue caused by this race is a crash while writing bitmap entries to the cache, because while the cache writeout task accesses the bitmaps, the trim task can be concurrently modifying the bitmap or worse might be freeing the bitmap. The later case results in the following crash: [55650.804460] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC [55650.804835] Modules linked in: btrfs dm_flakey dm_mod crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd fscache sunrpc loop parport_pc parport i2c_piix4 psmouse evdev pcspkr microcode processor i2ccore serio_raw thermal_sys button ext4 crc16 jbd2 mbcache sg sd_mod crc_t10dif sr_mod cdrom crct10dif_generic crct10dif_common ata_generic virtio_scsi floppy ata_piix libata virtio_pci virtio_ring virtio scsi_mod e1000 [last unloaded: btrfs] [55650.806169] CPU: 1 PID: 31002 Comm: btrfs-transacti Tainted: G W 3.17.0-rc5-btrfs-next-1+ #1 [55650.806493] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [55650.806867] task: ffff8800b12f6410 ti: ffff880071538000 task.ti: ffff880071538000 [55650.807166] RIP: 0010:[<ffffffffa037cf45>] [<ffffffffa037cf45>] write_bitmap_entries+0x65/0xbb [btrfs] [55650.807514] RSP: 0018:ffff88007153bc30 EFLAGS: 00010246 [55650.807687] RAX: 000000005d1ec000 RBX: ffff8800a665df08 RCX: 0000000000000400 [55650.807885] RDX: ffff88005d1ec000 RSI: 6b6b6b6b6b6b6b6b RDI: ffff88005d1ec000 [55650.808017] RBP: ffff88007153bc58 R08: 00000000ddd51536 R09: 00000000000001e0 [55650.808017] R10: 0000000000000000 R11: 0000000000000037 R12: 6b6b6b6b6b6b6b6b [55650.808017] R13: ffff88007153bca8 R14: 6b6b6b6b6b6b6b6b R15: ffff88007153bc98 [55650.808017] FS: 0000000000000000(0000) GS:ffff88023ec80000(0000) knlGS:0000000000000000 [55650.808017] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [55650.808017] CR2: 0000000002273b88 CR3: 00000000b18f6000 CR4: 00000000000006e0 [55650.808017] Stack: [55650.808017] ffff88020e834e00 ffff880172d68db0 0000000000000000 ffff88019257c800 [55650.808017] ffff8801d42ea720 ffff88007153bd10 ffffffffa037d2fa ffff880224e99180 [55650.808017] ffff8801469a6188 ffff880224e99140 ffff880172d68c50 00000003000000b7 [55650.808017] Call Trace: [55650.808017] [<ffffffffa037d2fa>] __btrfs_write_out_cache+0x1ea/0x37f [btrfs] [55650.808017] [<ffffffffa037d959>] btrfs_write_out_cache+0xa1/0xd8 [btrfs] [55650.808017] [<ffffffffa033936b>] btrfs_write_dirty_block_groups+0x4b5/0x505 [btrfs] [55650.808017] [<ffffffffa03aa98e>] commit_cowonly_roots+0x15e/0x1f7 [btrfs] [55650.808017] [<ffffffff813eb9c7>] ? _raw_spin_lock+0xe/0x10 [55650.808017] [<ffffffffa0346e46>] btrfs_commit_transaction+0x411/0x882 [btrfs] [55650.808017] [<ffffffffa03432a4>] transaction_kthread+0xf2/0x1a4 [btrfs] [55650.808017] [<ffffffffa03431b2>] ? btrfs_cleanup_transaction+0x3d8/0x3d8 [btrfs] [55650.808017] [<ffffffff8105966b>] kthread+0xb7/0xbf [55650.808017] [<ffffffff810595b4>] ? __kthread_parkme+0x67/0x67 [55650.808017] [<ffffffff813ebeac>] ret_from_fork+0x7c/0xb0 [55650.808017] [<ffffffff810595b4>] ? __kthread_parkme+0x67/0x67 [55650.808017] Code: 4c 89 ef 8d 70 ff e8 d4 fc ff ff 41 8b 45 34 41 39 45 30 7d 5c 31 f6 4c 89 ef e8 80 f6 ff ff 49 8b 7d 00 4c 89 f6 b9 00 04 00 00 <f3> a5 4c 89 ef 41 8b 45 30 8d 70 ff e8 a3 fc ff ff 41 8b 45 34 [55650.808017] RIP [<ffffffffa037cf45>] write_bitmap_entries+0x65/0xbb [btrfs] [55650.808017] RSP <ffff88007153bc30> [55650.815725] ---[ end trace 1c032e96b149ff86 ]--- Fix this by serializing both tasks in such a way that cache writeout doesn't wait for the trim/discard of free space entries to finish and doesn't miss any free space entry. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
Our fs trim operation, which is completely transactionless (doesn't start or joins an existing transaction) consists of visiting all block groups and then for each one to iterate its free space entries and perform a discard operation against the space range represented by the free space entries. However before performing a discard, the corresponding free space entry is removed from the free space rbtree, and when the discard completes it is added back to the free space rbtree. If a block group remove operation happens while the discard is ongoing (or before it starts and after a free space entry is hidden), we end up not waiting for the discard to complete, remove the extent map that maps logical address to physical addresses and the corresponding chunk metadata from the the chunk and device trees. After that and before the discard completes, the current running transaction can finish and a new one start, allowing for new block groups that map to the same physical addresses to be allocated and written to. So fix this by keeping the extent map in memory until the discard completes so that the same physical addresses aren't reused before it completes. If the physical locations that are under a discard operation end up being used for a new metadata block group for example, and dirty metadata extents are written before the discard finishes (the VM might call writepages() of our btree inode's i_mapping for example, or an fsync log commit happens) we end up overwriting metadata with zeroes, which leads to errors from fsck like the following: checking extents Check tree block failed, want=833912832, have=0 Check tree block failed, want=833912832, have=0 Check tree block failed, want=833912832, have=0 Check tree block failed, want=833912832, have=0 Check tree block failed, want=833912832, have=0 read block failed check_tree_block owner ref check failed [833912832 16384] Errors found in extent allocation tree or chunk allocation checking free space cache checking fs roots Check tree block failed, want=833912832, have=0 Check tree block failed, want=833912832, have=0 Check tree block failed, want=833912832, have=0 Check tree block failed, want=833912832, have=0 Check tree block failed, want=833912832, have=0 read block failed check_tree_block root 5 root dir 256 error root 5 inode 260 errors 2001, no inode item, link count wrong unresolved ref dir 256 index 0 namelen 8 name foobar_3 filetype 1 errors 6, no dir index, no inode ref root 5 inode 262 errors 2001, no inode item, link count wrong unresolved ref dir 256 index 0 namelen 8 name foobar_5 filetype 1 errors 6, no dir index, no inode ref root 5 inode 263 errors 2001, no inode item, link count wrong (...) Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Zhao Lei 提交于
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
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由 Filipe Manana 提交于
There's a race between adding a block group to the list of the unused block groups and removing an unused block group (cleaner kthread) that leads to freeing extents that are in use or a crash during transaction commmit. Basically the cleaner kthread, when executing btrfs_delete_unused_bgs(), might catch the newly added block group to the list fs_info->unused_bgs and clear the range representing the whole group from fs_info->freed_extents[] before the task that added the block group to the list (running update_block_group()) marked the last freed extent as dirty in fs_info->freed_extents (pinned_extents). That is: CPU 1 CPU 2 btrfs_delete_unused_bgs() update_block_group() add block group to fs_info->unused_bgs got block group from the list clear_extent_bits for the whole block group range in freed_extents[] set_extent_dirty for the range covering the freed extent in freed_extents[] (fs_info->pinned_extents) block group deleted, and a new block group with the same logical address is created reserve space from the new block group for new data or metadata - the reserved space overlaps the range specified by CPU 1 for set_extent_dirty() commit transaction find all ranges marked as dirty in fs_info->pinned_extents, clear them and add them to the free space cache Alternatively, if CPU 2 doesn't create a new block group with the same logical address, we get a crash/BUG_ON at transaction commit when unpining extent ranges because we can't find a block group for the range marked as dirty by CPU 1. Sample trace: [ 2163.426462] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC [ 2163.426640] Modules linked in: btrfs xor raid6_pq dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio crc32c_generic libcrc32c dm_mod nfsd auth_rpc gss oid_registry nfs_acl nfs lockd fscache sunrpc loop psmouse parport_pc parport i2c_piix4 processor thermal_sys i2ccore evdev button pcspkr microcode serio_raw ext4 crc16 jbd2 mbcache sg sr_mod cdrom sd_mod crc_t10dif crct10dif_generic crct10dif_common ata_generic virtio_scsi floppy ata_piix libata e1000 scsi_mod virtio_pci virtio_ring virtio [ 2163.428209] CPU: 0 PID: 11858 Comm: btrfs-transacti Tainted: G W 3.17.0-rc5-btrfs-next-1+ #1 [ 2163.428519] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [ 2163.428875] task: ffff88009f2c0650 ti: ffff8801356bc000 task.ti: ffff8801356bc000 [ 2163.429157] RIP: 0010:[<ffffffffa037728e>] [<ffffffffa037728e>] unpin_extent_range.isra.58+0x62/0x192 [btrfs] [ 2163.429562] RSP: 0018:ffff8801356bfda8 EFLAGS: 00010246 [ 2163.429802] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 2163.429990] RDX: 0000000041bfffff RSI: 0000000001c00000 RDI: ffff880024307080 [ 2163.430042] RBP: ffff8801356bfde8 R08: 0000000000000068 R09: ffff88003734f118 [ 2163.430042] R10: ffff8801356bfcb8 R11: fffffffffffffb69 R12: ffff8800243070d0 [ 2163.430042] R13: 0000000083c04000 R14: ffff8800751b0f00 R15: ffff880024307000 [ 2163.430042] FS: 0000000000000000(0000) GS:ffff88013f400000(0000) knlGS:0000000000000000 [ 2163.430042] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 2163.430042] CR2: 00007ff10eb43fc0 CR3: 0000000004cb8000 CR4: 00000000000006f0 [ 2163.430042] Stack: [ 2163.430042] ffff8800243070d0 0000000083c08000 0000000083c07fff ffff88012d6bc800 [ 2163.430042] ffff8800243070d0 ffff8800751b0f18 ffff8800751b0f00 0000000000000000 [ 2163.430042] ffff8801356bfe18 ffffffffa037a481 0000000083c04000 0000000083c07fff [ 2163.430042] Call Trace: [ 2163.430042] [<ffffffffa037a481>] btrfs_finish_extent_commit+0xac/0xbf [btrfs] [ 2163.430042] [<ffffffffa038c06d>] btrfs_commit_transaction+0x6ee/0x882 [btrfs] [ 2163.430042] [<ffffffffa03881f1>] transaction_kthread+0xf2/0x1a4 [btrfs] [ 2163.430042] [<ffffffffa03880ff>] ? btrfs_cleanup_transaction+0x3d8/0x3d8 [btrfs] [ 2163.430042] [<ffffffff8105966b>] kthread+0xb7/0xbf [ 2163.430042] [<ffffffff810595b4>] ? __kthread_parkme+0x67/0x67 [ 2163.430042] [<ffffffff813ebeac>] ret_from_fork+0x7c/0xb0 [ 2163.430042] [<ffffffff810595b4>] ? __kthread_parkme+0x67/0x67 So fix this by making update_block_group() first set the range as dirty in pinned_extents before adding the block group to the unused_bgs list. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Reviewed-by: NJosef Bacik <jbacik@fb.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
If we remove a block group (because it became empty), we might have left a caching_ctl structure in fs_info->caching_block_groups that points to the block group and is accessed at transaction commit time. This results in accessing an invalid or incorrect block group. This issue became visible after Josef's patch "Btrfs: remove empty block groups automatically". So if the block group is removed make sure we don't leave a dangling caching_ctl in caching_block_groups. Sample crash trace: [58380.439449] BUG: unable to handle kernel paging request at ffff8801446eaeb8 [58380.439707] IP: [<ffffffffa03f6d05>] block_group_cache_done.isra.21+0xc/0x1c [btrfs] [58380.440879] PGD 1acb067 PUD 23f5ff067 PMD 23f5db067 PTE 80000001446ea060 [58380.441220] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC [58380.441486] Modules linked in: btrfs crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd fscache sunrpc loop psmouse processor i2c_piix4 parport_pc parport pcspkr serio_raw evdev i2ccore thermal_sys microcode button ext4 crc16 jbd2 mbcache sr_mod cdrom ata_generic sg sd_mod crc_t10dif crct10dif_generic crct10dif_common virtio_scsi floppy ata_piix e1000 libata virtio_pci scsi_mod virtio_ring virtio [last unloaded: btrfs] [58380.443238] CPU: 3 PID: 25728 Comm: btrfs-transacti Tainted: G W 3.17.0-rc5-btrfs-next-1+ #1 [58380.443238] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [58380.443238] task: ffff88013ac82090 ti: ffff88013896c000 task.ti: ffff88013896c000 [58380.443238] RIP: 0010:[<ffffffffa03f6d05>] [<ffffffffa03f6d05>] block_group_cache_done.isra.21+0xc/0x1c [btrfs] [58380.443238] RSP: 0018:ffff88013896fdd8 EFLAGS: 00010283 [58380.443238] RAX: ffff880222cae850 RBX: ffff880119ba74c0 RCX: 0000000000000000 [58380.443238] RDX: 0000000000000000 RSI: ffff880185e16800 RDI: ffff8801446eaeb8 [58380.443238] RBP: ffff88013896fdd8 R08: ffff8801a9ca9fa8 R09: ffff88013896fc60 [58380.443238] R10: ffff88013896fd28 R11: 0000000000000000 R12: ffff880222cae000 [58380.443238] R13: ffff880222cae850 R14: ffff880222cae6b0 R15: ffff8801446eae00 [58380.443238] FS: 0000000000000000(0000) GS:ffff88023ed80000(0000) knlGS:0000000000000000 [58380.443238] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [58380.443238] CR2: ffff8801446eaeb8 CR3: 0000000001811000 CR4: 00000000000006e0 [58380.443238] Stack: [58380.443238] ffff88013896fe18 ffffffffa03fe2d5 ffff880222cae850 ffff880185e16800 [58380.443238] ffff88000dc41c20 0000000000000000 ffff8801a9ca9f00 0000000000000000 [58380.443238] ffff88013896fe80 ffffffffa040fbcf ffff88018b0dcdb0 ffff88013ac82090 [58380.443238] Call Trace: [58380.443238] [<ffffffffa03fe2d5>] btrfs_prepare_extent_commit+0x5a/0xd7 [btrfs] [58380.443238] [<ffffffffa040fbcf>] btrfs_commit_transaction+0x45c/0x882 [btrfs] [58380.443238] [<ffffffffa040c058>] transaction_kthread+0xf2/0x1a4 [btrfs] [58380.443238] [<ffffffffa040bf66>] ? btrfs_cleanup_transaction+0x3d8/0x3d8 [btrfs] [58380.443238] [<ffffffff8105966b>] kthread+0xb7/0xbf [58380.443238] [<ffffffff810595b4>] ? __kthread_parkme+0x67/0x67 [58380.443238] [<ffffffff813ebeac>] ret_from_fork+0x7c/0xb0 [58380.443238] [<ffffffff810595b4>] ? __kthread_parkme+0x67/0x67 Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
If we grab a block group, for example in btrfs_trim_fs(), we will be holding a reference on it but the block group can be removed after we got it (via btrfs_remove_block_group), which means it will no longer be part of the rbtree. However, btrfs_remove_block_group() was only calling rb_erase() which leaves the block group's rb_node left and right child pointers with the same content they had before calling rb_erase. This was dangerous because a call to next_block_group() would access the node's left and right child pointers (via rb_next), which can be no longer valid. Fix this by clearing a block group's node after removing it from the tree, and have next_block_group() do a tree search to get the next block group instead of using rb_next() if our block group was removed. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Reviewed-by: NJosef Bacik <jbacik@fb.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Miao Xie 提交于
The commit c404e0dc (Btrfs: fix use-after-free in the finishing procedure of the device replace) fixed a use-after-free problem which happened when removing the source device at the end of device replace, but at that time, btrfs didn't support device replace on raid56, so we didn't fix the problem on the raid56 profile. Currently, we implemented device replace for raid56, so we need kick that problem out before we enable that function for raid56. The fix method is very simple, we just increase the bio per-cpu counter before we submit a raid56 io, and decrease the counter when the raid56 io ends. Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
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由 Miao Xie 提交于
This function reused the code of parity scrub, and we just write the right parity or corrected parity into the target device before the parity scrub end. Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
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由 Miao Xie 提交于
The implementation is simple: - In order to avoid changing the code logic of btrfs_map_bio and RAID56, we add the stripes of the replace target devices at the end of the stripe array in btrfs bio, and we sort those target device stripes in the array. And we keep the number of the target device stripes in the btrfs bio. - Except write operation on RAID56, all the other operation don't take the target device stripes into account. - When we do write operation, we read the data from the common devices and calculate the parity. Then write the dirty data and new parity out, at this time, we will find the relative replace target stripes and wirte the relative data into it. Note: The function that copying old data on the source device to the target device was implemented in the past, it is similar to the other RAID type. Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
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由 Miao Xie 提交于
The implementation is: - Read and check all the data with checksum in the same stripe. All the data which has checksum is COW data, and we are sure that it is not changed though we don't lock the stripe. because the space of that data just can be reclaimed after the current transction is committed, and then the fs can use it to store the other data, but when doing scrub, we hold the current transaction, that is that data can not be recovered, it is safe that read and check it out of the stripe lock. - Lock the stripe - Read out all the data without checksum and parity The data without checksum and the parity may be changed if we don't lock the stripe, so we need read it in the stripe lock context. - Check the parity - Re-calculate the new parity and write back it if the old parity is not right - Unlock the stripe If we can not read out the data or the data we read is corrupted, we will try to repair it. If the repair fails. we will mark the horizontal sub-stripe(pages on the same horizontal) as corrupted sub-stripe, and we will skip the parity check and repair of that horizontal sub-stripe. And in order to skip the horizontal sub-stripe that has no data, we introduce a bitmap. If there is some data on the horizontal sub-stripe, we will the relative bit to 1, and when we check and repair the parity, we will skip those horizontal sub-stripes that the relative bits is 0. Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
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由 Miao Xie 提交于
We will introduce new operation type later, if we still use integer variant as bool variant to record the operation type, we would add new variant and increase the size of raid bio structure. It is not good, by this patch, we define different number for different operation, and we can just use a variant to record the operation type. Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
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由 Miao Xie 提交于
This patch implement the RAID5/6 common data repair function, the implementation is similar to the scrub on the other RAID such as RAID1, the differentia is that we don't read the data from the mirror, we use the data repair function of RAID5/6. Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
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由 Miao Xie 提交于
Because we will reuse bbio and raid_map during the scrub later, it is better that we don't change any variant of bbio and don't free it at the end of IO request. So we introduced similar variants into the raid bio, and don't access those bbio's variants any more. Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
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由 Zhao Lei 提交于
stripe_index's value was set again in latter line: stripe_index = 0; Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com> Reviewed-by: NDavid Sterba <dsterba@suse.cz>
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由 Zhao Lei 提交于
bbio_ret in this condition is always !NULL because previous code already have a check-and-skip: 4908 if (!bbio_ret) 4909 goto out; Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com> Reviewed-by: NDavid Sterba <dsterba@suse.cz>
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- 25 11月, 2014 6 次提交
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由 Filipe Manana 提交于
If right after starting the snapshot creation ioctl we perform a write against a file followed by a truncate, with both operations increasing the file's size, we can get a snapshot tree that reflects a state of the source subvolume's tree where the file truncation happened but the write operation didn't. This leaves a gap between 2 file extent items of the inode, which makes btrfs' fsck complain about it. For example, if we perform the following file operations: $ mkfs.btrfs -f /dev/vdd $ mount /dev/vdd /mnt $ xfs_io -f \ -c "pwrite -S 0xaa -b 32K 0 32K" \ -c "fsync" \ -c "pwrite -S 0xbb -b 32770 16K 32770" \ -c "truncate 90123" \ /mnt/foobar and the snapshot creation ioctl was just called before the second write, we often can get the following inode items in the snapshot's btree: item 120 key (257 INODE_ITEM 0) itemoff 7987 itemsize 160 inode generation 146 transid 7 size 90123 block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0 flags 0x0 item 121 key (257 INODE_REF 256) itemoff 7967 itemsize 20 inode ref index 282 namelen 10 name: foobar item 122 key (257 EXTENT_DATA 0) itemoff 7914 itemsize 53 extent data disk byte 1104855040 nr 32768 extent data offset 0 nr 32768 ram 32768 extent compression 0 item 123 key (257 EXTENT_DATA 53248) itemoff 7861 itemsize 53 extent data disk byte 0 nr 0 extent data offset 0 nr 40960 ram 40960 extent compression 0 There's a file range, corresponding to the interval [32K; ALIGN(16K + 32770, 4096)[ for which there's no file extent item covering it. This is because the file write and file truncate operations happened both right after the snapshot creation ioctl called btrfs_start_delalloc_inodes(), which means we didn't start and wait for the ordered extent that matches the write and, in btrfs_setsize(), we were able to call btrfs_cont_expand() before being able to commit the current transaction in the snapshot creation ioctl. So this made it possibe to insert the hole file extent item in the source subvolume (which represents the region added by the truncate) right before the transaction commit from the snapshot creation ioctl. Btrfs' fsck tool complains about such cases with a message like the following: "root 331 inode 257 errors 100, file extent discount" >From a user perspective, the expectation when a snapshot is created while those file operations are being performed is that the snapshot will have a file that either: 1) is empty 2) only the first write was captured 3) only the 2 writes were captured 4) both writes and the truncation were captured But never capture a state where only the first write and the truncation were captured (since the second write was performed before the truncation). A test case for xfstests follows. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
Move the logic from the snapshot creation ioctl into send. This avoids doing the transaction commit if send isn't used, and ensures that if a crash/reboot happens after the transaction commit that created the snapshot and before the transaction commit that switched the commit root, send will not get a commit root that differs from the main root (that has orphan items). Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
Due to ignoring errors returned by clear_extent_bits (at the moment only -ENOMEM is possible), we can end up freeing an extent that is actually in use (i.e. return the extent to the free space cache). The sequence of steps that lead to this: 1) Cleaner thread starts execution and calls btrfs_delete_unused_bgs(), with the goal of freeing empty block groups; 2) btrfs_delete_unused_bgs() finds an empty block group, joins the current transaction (or starts a new one if none is running) and attempts to clear the EXTENT_DIRTY bit for the block group's range from freed_extents[0] and freed_extents[1] (of which one corresponds to fs_info->pinned_extents); 3) Clearing the EXTENT_DIRTY bit (via clear_extent_bits()) fails with -ENOMEM, but such error is ignored and btrfs_delete_unused_bgs() proceeds to delete the block group and the respective chunk, while pinned_extents remains with that bit set for the whole (or a part of the) range covered by the block group; 4) Later while the transaction is still running, the chunk ends up being reused for a new block group (maybe for different purpose, data or metadata), and extents belonging to the new block group are allocated for file data or btree nodes/leafs; 5) The current transaction is committed, meaning that we unpinned one or more extents from the new block group (through btrfs_finish_extent_commit() and unpin_extent_range()) which are now being used for new file data or new metadata (through btrfs_finish_extent_commit() and unpin_extent_range()). And unpinning means we returned the extents to the free space cache of the new block group, which implies those extents can be used for future allocations while they're still in use. Alternatively, we can hit a BUG_ON() when doing a lookup for a block group's cache object in unpin_extent_range() if a new block group didn't end up being allocated for the same chunk (step 4 above). Fix this by not freeing the block group and chunk if we fail to clear the dirty bit. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Chris Mason 提交于
Fengguang's build monster reported warnings on some arches because we don't have vmalloc.h included Signed-off-by: NChris Mason <clm@fb.com> Reported-by: fengguang.wu@intel.com
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由 Qu Wenruo 提交于
The following lockdep warning is triggered during xfstests: [ 1702.980872] ========================================================= [ 1702.981181] [ INFO: possible irq lock inversion dependency detected ] [ 1702.981482] 3.18.0-rc1 #27 Not tainted [ 1702.981781] --------------------------------------------------------- [ 1702.982095] kswapd0/77 just changed the state of lock: [ 1702.982415] (&delayed_node->mutex){+.+.-.}, at: [<ffffffffa03b0b51>] __btrfs_release_delayed_node+0x41/0x1f0 [btrfs] [ 1702.982794] but this lock took another, RECLAIM_FS-unsafe lock in the past: [ 1702.983160] (&fs_info->dev_replace.lock){+.+.+.} and interrupts could create inverse lock ordering between them. [ 1702.984675] other info that might help us debug this: [ 1702.985524] Chain exists of: &delayed_node->mutex --> &found->groups_sem --> &fs_info->dev_replace.lock [ 1702.986799] Possible interrupt unsafe locking scenario: [ 1702.987681] CPU0 CPU1 [ 1702.988137] ---- ---- [ 1702.988598] lock(&fs_info->dev_replace.lock); [ 1702.989069] local_irq_disable(); [ 1702.989534] lock(&delayed_node->mutex); [ 1702.990038] lock(&found->groups_sem); [ 1702.990494] <Interrupt> [ 1702.990938] lock(&delayed_node->mutex); [ 1702.991407] *** DEADLOCK *** It is because the btrfs_kobj_{add/rm}_device() will call memory allocation with GFP_KERNEL, which may flush fs page cache to free space, waiting for it self to do the commit, causing the deadlock. To solve the problem, move btrfs_kobj_{add/rm}_device() out of the dev_replace lock range, also involing split the btrfs_rm_dev_replace_srcdev() function into remove and free parts. Now only btrfs_rm_dev_replace_remove_srcdev() is called in dev_replace lock range, and kobj_{add/rm} and btrfs_rm_dev_replace_free_srcdev() are called out of the lock range. Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Chris Mason 提交于
Merge branch 'dev/pending-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus
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- 24 11月, 2014 10 次提交
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由 Linus Torvalds 提交于
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由 Andy Lutomirski 提交于
x86 call do_notify_resume on paranoid returns if TIF_UPROBE is set but not on non-paranoid returns. I suspect that this is a mistake and that the code only works because int3 is paranoid. Setting _TIF_NOTIFY_RESUME in the uprobe code was probably a workaround for the x86 bug. With that bug fixed, we can remove _TIF_NOTIFY_RESUME from the uprobes code. Reported-by: NOleg Nesterov <oleg@redhat.com> Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: NBorislav Petkov <bp@suse.de> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Thomas Gleixner 提交于
Chris bisected a NULL pointer deference in task_sched_runtime() to commit 6e998916 'sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency'. Chris observed crashes in atop or other /proc walking programs when he started fork bombs on his machine. He assumed that this is a new exit race, but that does not make any sense when looking at that commit. What's interesting is that, the commit provides update_curr callbacks for all scheduling classes except stop_task and idle_task. While nothing can ever hit that via the clock_nanosleep() and clock_gettime() interfaces, which have been the target of the commit in question, the author obviously forgot that there are other code paths which invoke task_sched_runtime() do_task_stat(() thread_group_cputime_adjusted() thread_group_cputime() task_cputime() task_sched_runtime() if (task_current(rq, p) && task_on_rq_queued(p)) { update_rq_clock(rq); up->sched_class->update_curr(rq); } If the stats are read for a stomp machine task, aka 'migration/N' and that task is current on its cpu, this will happily call the NULL pointer of stop_task->update_curr. Ooops. Chris observation that this happens faster when he runs the fork bomb makes sense as the fork bomb will kick migration threads more often so the probability to hit the issue will increase. Add the missing update_curr callbacks to the scheduler classes stop_task and idle_task. While idle tasks cannot be monitored via /proc we have other means to hit the idle case. Fixes: 6e998916 'sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency' Reported-by: NChris Mason <clm@fb.com> Reported-and-tested-by: NBorislav Petkov <bp@alien8.de> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
Merge x86-64 iret fixes from Andy Lutomirski: "This addresses the following issues: - an unrecoverable double-fault triggerable with modify_ldt. - invalid stack usage in espfix64 failed IRET recovery from IST context. - invalid stack usage in non-espfix64 failed IRET recovery from IST context. It also makes a good but IMO scary change: non-espfix64 failed IRET will now report the correct error. Hopefully nothing depended on the old incorrect behavior, but maybe Wine will get confused in some obscure corner case" * emailed patches from Andy Lutomirski <luto@amacapital.net>: x86_64, traps: Rework bad_iret x86_64, traps: Stop using IST for #SS x86_64, traps: Fix the espfix64 #DF fixup and rewrite it in C
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由 Andy Lutomirski 提交于
It's possible for iretq to userspace to fail. This can happen because of a bad CS, SS, or RIP. Historically, we've handled it by fixing up an exception from iretq to land at bad_iret, which pretends that the failed iret frame was really the hardware part of #GP(0) from userspace. To make this work, there's an extra fixup to fudge the gs base into a usable state. This is suboptimal because it loses the original exception. It's also buggy because there's no guarantee that we were on the kernel stack to begin with. For example, if the failing iret happened on return from an NMI, then we'll end up executing general_protection on the NMI stack. This is bad for several reasons, the most immediate of which is that general_protection, as a non-paranoid idtentry, will try to deliver signals and/or schedule from the wrong stack. This patch throws out bad_iret entirely. As a replacement, it augments the existing swapgs fudge into a full-blown iret fixup, mostly written in C. It's should be clearer and more correct. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Reviewed-by: NThomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andy Lutomirski 提交于
On a 32-bit kernel, this has no effect, since there are no IST stacks. On a 64-bit kernel, #SS can only happen in user code, on a failed iret to user space, a canonical violation on access via RSP or RBP, or a genuine stack segment violation in 32-bit kernel code. The first two cases don't need IST, and the latter two cases are unlikely fatal bugs, and promoting them to double faults would be fine. This fixes a bug in which the espfix64 code mishandles a stack segment violation. This saves 4k of memory per CPU and a tiny bit of code. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Reviewed-by: NThomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andy Lutomirski 提交于
There's nothing special enough about the espfix64 double fault fixup to justify writing it in assembly. Move it to C. This also fixes a bug: if the double fault came from an IST stack, the old asm code would return to a partially uninitialized stack frame. Fixes: 3891a04aSigned-off-by: NAndy Lutomirski <luto@amacapital.net> Reviewed-by: NThomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc由 Linus Torvalds 提交于
Pull ARM SoC fixes from Olof Johansson: "A collection of fixes this week: - A set of clock fixes for shmobile platforms - A fix for tegra that moves serial port labels to be per board. We're choosing to merge this for 3.18 because the labels will start being parsed in 3.19, and without this change serial port numbers that used to be stable since the dawn of time will change numbers. - A few other DT tweaks for Tegra. - A fix for multi_v7_defconfig that makes it stop spewing cpufreq errors on Arndale (Exynos)" * tag 'armsoc-for-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: ARM: multi_v7_defconfig: fix failure setting CPU voltage by enabling dependent I2C controller ARM: tegra: roth: Fix SD card VDD_IO regulator ARM: tegra: Remove eMMC vmmc property for roth/tn7 ARM: dts: tegra: move serial aliases to per-board ARM: tegra: Add serial port labels to Tegra124 DT ARM: shmobile: kzm9g legacy: Set i2c clks_per_count to 2 ARM: shmobile: r8a7740 dtsi: Correct IIC0 parent clock ARM: shmobile: r8a7790: Fix SD3CKCR address to device tree ARM: shmobile: r8a7740 legacy: Correct IIC0 parent clock ARM: shmobile: r8a7740 legacy: Add missing INTCA clock for irqpin module ARM: shmobile: r8a7790: Fix SD3CKCR address ARM: dts: sun6i: Re-parent ahb1_mux to pll6 as required by dma controller
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu由 Linus Torvalds 提交于
Pull percpu fix from Tejun Heo: "This contains one patch to fix a race condition which can lead to percpu_ref using a percpu pointer which is corrupted with a set DEAD bit. The bug was introduced while separating out the ATOMIC mode flag from the DEAD flag. The fix is pretty straight forward. I just committed the patch to the percpu tree but am sending out the pull request early as I'll be on vacation for a week. The patch should be fairly safe and while the latency will be higher I'll be checking emails" * 'for-3.18-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: percpu-ref: fix DEAD flag contamination of percpu pointer
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git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs由 Linus Torvalds 提交于
Pull btrfs deadlock fix from Chris Mason: "This has a fix for a long standing deadlock that we've been trying to nail down for a while. It ended up being a bad interaction with the fair reader/writer locks and the order btrfs reacquires locks in the btree" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: btrfs: fix lockups from btrfs_clear_path_blocking
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