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Filipe Manana 0bb7883009 btrfs: fix sleep while in non-sleep context during qgroup removal
While removing a qgroup's sysfs entry we end up taking the kernfs_mutex,
through kobject_del(), while holding the fs_info->qgroup_lock spinlock,
producing the following trace:

  [821.843637] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:281
  [821.843641] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 28214, name: podman
  [821.843644] CPU: 3 PID: 28214 Comm: podman Tainted: G        W         5.11.6 #15
  [821.843646] Hardware name: Dell Inc. PowerEdge R330/084XW4, BIOS 2.11.0 12/08/2020
  [821.843647] Call Trace:
  [821.843650]  dump_stack+0xa1/0xfb
  [821.843656]  ___might_sleep+0x144/0x160
  [821.843659]  mutex_lock+0x17/0x40
  [821.843662]  kernfs_remove_by_name_ns+0x1f/0x80
  [821.843666]  sysfs_remove_group+0x7d/0xe0
  [821.843668]  sysfs_remove_groups+0x28/0x40
  [821.843670]  kobject_del+0x2a/0x80
  [821.843672]  btrfs_sysfs_del_one_qgroup+0x2b/0x40 [btrfs]
  [821.843685]  __del_qgroup_rb+0x12/0x150 [btrfs]
  [821.843696]  btrfs_remove_qgroup+0x288/0x2a0 [btrfs]
  [821.843707]  btrfs_ioctl+0x3129/0x36a0 [btrfs]
  [821.843717]  ? __mod_lruvec_page_state+0x5e/0xb0
  [821.843719]  ? page_add_new_anon_rmap+0xbc/0x150
  [821.843723]  ? kfree+0x1b4/0x300
  [821.843725]  ? mntput_no_expire+0x55/0x330
  [821.843728]  __x64_sys_ioctl+0x5a/0xa0
  [821.843731]  do_syscall_64+0x33/0x70
  [821.843733]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [821.843736] RIP: 0033:0x4cd3fb
  [821.843741] RSP: 002b:000000c000906b20 EFLAGS: 00000206 ORIG_RAX: 0000000000000010
  [821.843744] RAX: ffffffffffffffda RBX: 000000c000050000 RCX: 00000000004cd3fb
  [821.843745] RDX: 000000c000906b98 RSI: 000000004010942a RDI: 000000000000000f
  [821.843747] RBP: 000000c000907cd0 R08: 000000c000622901 R09: 0000000000000000
  [821.843748] R10: 000000c000d992c0 R11: 0000000000000206 R12: 000000000000012d
  [821.843749] R13: 000000000000012c R14: 0000000000000200 R15: 0000000000000049

Fix this by removing the qgroup sysfs entry while not holding the spinlock,
since the spinlock is only meant for protection of the qgroup rbtree.

Reported-by: Stuart Shelton <srcshelton@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/7A5485BB-0628-419D-A4D3-27B1AF47E25A@gmail.com/
Fixes: 49e5fb4621 ("btrfs: qgroup: export qgroups in sysfs")
CC: stable@vger.kernel.org # 5.10+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-18 16:53:24 +01:00
arch - For syscall user dispatch, separate ptctl operation from syscall 2021-02-07 10:16:24 -08:00
block block: add bio_add_zone_append_page 2021-02-09 00:52:19 +01:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto X.509: Fix crash caused by NULL pointer 2021-01-20 11:33:51 -08:00
Documentation - For syscall user dispatch, separate ptctl operation from syscall 2021-02-07 10:16:24 -08:00
drivers libnvdimm for 5.11-rc7 2021-02-07 10:45:26 -08:00
fs btrfs: fix sleep while in non-sleep context during qgroup removal 2021-03-18 16:53:24 +01:00
include iomap: support REQ_OP_ZONE_APPEND 2021-02-09 00:52:19 +01:00
init init/gcov: allow CONFIG_CONSTRUCTORS on UML to fix module gcov 2021-02-05 11:03:47 -08:00
ipc Merge branch 'akpm' (patches from Andrew) 2020-12-15 12:53:37 -08:00
kernel tracing: Fix output of top level event "enable" file 2021-02-08 11:32:39 -08:00
lib - Revert an attempt to not spread IRQ threads on isolated CPUs which has 2021-02-07 10:03:43 -08:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm: hugetlb: fix missing put_page in gather_surplus_pages() 2021-02-05 11:03:47 -08:00
net Fixes: 2021-02-05 10:11:14 -08:00
samples ARM: SoC drivers for v5.11 2020-12-16 16:38:41 -08:00
scripts kallsyms: fix nonconverging kallsyms table with lld 2021-02-05 17:53:28 +09:00
security cap: fix conversions on getxattr 2021-01-28 10:22:48 +01:00
sound ALSA: hda/via: Apply the workaround generically for Clevo machines 2021-01-26 18:05:03 +01:00
tools libnvdimm for 5.11-rc7 2021-02-07 10:45:26 -08:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM/arm64 fixes for 5.11, take #2 2021-01-25 18:52:01 -05:00
.clang-format clang-format: Update with the latest for_each macro list 2021-01-29 15:00:23 +01:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap block-5.11-2021-02-05 2021-02-06 14:40:27 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: dccp: move Gerrit Renker to CREDITS 2021-01-14 10:53:49 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS/.mailmap: use my @kernel.org address 2021-02-05 11:03:47 -08:00
Makefile Linux 5.11-rc7 2021-02-07 13:57:38 -08:00
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.