Linux mainline fork with MSM8998 patches | https://mainline.space | Currently supported devices: OnePlus 5/5T, Xiaomi Mi 6, F(x)tec Pro¹ (2019 QX1000 model) & Sony Xperia XZ Premium (UNTESTED!)
Find a file
Qu Wenruo 62fdaa52a3 btrfs: Detect unbalanced tree with empty leaf before crashing btree operations
[BUG]
With crafted image, btrfs will panic at btree operations:

  kernel BUG at fs/btrfs/ctree.c:3894!
  invalid opcode: 0000 [#1] SMP PTI
  CPU: 0 PID: 1138 Comm: btrfs-transacti Not tainted 5.0.0-rc8+ #9
  RIP: 0010:__push_leaf_left+0x6b6/0x6e0
  RSP: 0018:ffffc0bd4128b990 EFLAGS: 00010246
  RAX: 0000000000000000 RBX: ffffa0a4ab8f0e38 RCX: 0000000000000000
  RDX: ffffa0a280000000 RSI: 0000000000000000 RDI: ffffa0a4b3814000
  RBP: ffffc0bd4128ba38 R08: 0000000000001000 R09: ffffc0bd4128b948
  R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000240
  R13: ffffa0a4b556fb60 R14: ffffa0a4ab8f0af0 R15: ffffa0a4ab8f0af0
  FS: 0000000000000000(0000) GS:ffffa0a4b7a00000(0000) knlGS:0000000000000000
  CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f2461c80020 CR3: 000000022b32a006 CR4: 00000000000206f0
  Call Trace:
  ? _cond_resched+0x1a/0x50
  push_leaf_left+0x179/0x190
  btrfs_del_items+0x316/0x470
  btrfs_del_csums+0x215/0x3a0
  __btrfs_free_extent.isra.72+0x5a7/0xbe0
  __btrfs_run_delayed_refs+0x539/0x1120
  btrfs_run_delayed_refs+0xdb/0x1b0
  btrfs_commit_transaction+0x52/0x950
  ? start_transaction+0x94/0x450
  transaction_kthread+0x163/0x190
  kthread+0x105/0x140
  ? btrfs_cleanup_transaction+0x560/0x560
  ? kthread_destroy_worker+0x50/0x50
  ret_from_fork+0x35/0x40
  Modules linked in:
  ---[ end trace c2425e6e89b5558f ]---

[CAUSE]
The offending csum tree looks like this:

  checksum tree key (CSUM_TREE ROOT_ITEM 0)
  node 29741056 level 1 items 14 free 107 generation 19 owner CSUM_TREE
	  ...
	  key (EXTENT_CSUM EXTENT_CSUM 85975040) block 29630464 gen 17
	  key (EXTENT_CSUM EXTENT_CSUM 89911296) block 29642752 gen 17 <<<
	  key (EXTENT_CSUM EXTENT_CSUM 92274688) block 29646848 gen 17
	  ...

  leaf 29630464 items 6 free space 1 generation 17 owner CSUM_TREE
	  item 0 key (EXTENT_CSUM EXTENT_CSUM 85975040) itemoff 3987 itemsize 8
		  range start 85975040 end 85983232 length 8192
	  ...
  leaf 29642752 items 0 free space 3995 generation 17 owner 0
		      ^ empty leaf            invalid owner ^

  leaf 29646848 items 1 free space 602 generation 17 owner CSUM_TREE
	  item 0 key (EXTENT_CSUM EXTENT_CSUM 92274688) itemoff 627 itemsize 3368
		  range start 92274688 end 95723520 length 3448832

So we have a corrupted csum tree where one tree leaf is completely
empty, causing unbalanced btree, thus leading to unexpected btree
balance error.

[FIX]
For this particular case, we handle it in two directions to catch it:
- Check if the tree block is empty through btrfs_verify_level_key()
  So that invalid tree blocks won't be read out through
  btrfs_search_slot() and its variants.

- Check 0 tree owner in tree checker
  NO tree is using 0 as its tree owner, detect it and reject at tree
  block read time.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202821
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09 14:59:14 +02:00
arch Revert "x86/apic: Include the LDR when clearing out APIC registers" 2019-09-07 14:25:54 -07:00
block block: remove REQ_NOWAIT_INLINE 2019-08-15 11:09:16 -06:00
certs Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
crypto USB / PHY patches for 5.3-rc1 2019-07-11 15:40:06 -07:00
Documentation Documentation/process: Add Qualcomm process ambassador for hardware security issues 2019-09-07 18:30:54 +01:00
drivers GPIO fixes for the v5.3 series: 2019-09-08 09:30:31 -07:00
fs btrfs: Detect unbalanced tree with empty leaf before crashing btree operations 2019-09-09 14:59:14 +02:00
include btrfs: replace: BTRFS_DEV_REPLACE_ITEM_STATE_x defines should go 2019-09-09 14:59:11 +02:00
init Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
ipc Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
kernel sched/core: Fix uclamp ABI bug, clean up and robustify sched_read_attr() ABI logic and code 2019-09-04 19:51:30 +02:00
lib Partially revert "kfifo: fix kfifo_alloc() and kfifo_init()" 2019-08-30 18:47:15 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/balloon_compaction: suppress allocation warnings 2019-09-04 07:42:01 -04:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-09-01 18:45:28 -07:00
samples auxdisplay: Fix a typo in cfag12864b-example.c 2019-08-08 20:00:18 +02:00
scripts SPDX fixes for 5.3-rc5 2019-08-18 09:26:16 -07:00
security keys: Fix missing null pointer check in request_key_auth_describe() 2019-09-05 14:19:25 -07:00
sound sound fixes for 5.3-rc8 2019-09-05 10:26:20 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-09-01 18:45:28 -07:00
usr kbuild: enable arch/s390/include/uapi/asm/zcrypt.h for uapi header test 2019-07-23 10:45:46 +02:00
virt arm64 fixes for -rc7 2019-08-28 10:37:21 -07:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: Add compilation database file 2019-07-27 12:18:19 +09:00
.mailmap mailmap: add aliases for Dmitry Safonov 2019-08-30 18:00:50 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Remove references to dead website. 2019-07-19 12:22:04 -07:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Char/Misc driver fixes for 5.3-rc7 2019-09-02 09:30:34 -07:00
Makefile Linux 5.3-rc8 2019-09-08 13:33:15 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.