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Johannes Thumshirn a5bc4e030f btrfs: don't take dev_replace rwsem on task already holding it 
[ Upstream commit 8cca35cb29 ]

Running fstests btrfs/011 with MKFS_OPTIONS="-O rst" to force the usage of
the RAID stripe-tree, we get the following splat from lockdep:

 BTRFS info (device sdd): dev_replace from /dev/sdd (devid 1) to /dev/sdb started

 ============================================
 WARNING: possible recursive locking detected
 6.11.0-rc3-btrfs-for-next #599 Not tainted
 --------------------------------------------
 btrfs/2326 is trying to acquire lock:
 ffff88810f215c98 (&fs_info->dev_replace.rwsem){++++}-{3:3}, at: btrfs_map_block+0x39f/0x2250

 but task is already holding lock:
 ffff88810f215c98 (&fs_info->dev_replace.rwsem){++++}-{3:3}, at: btrfs_map_block+0x39f/0x2250

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&fs_info->dev_replace.rwsem);
   lock(&fs_info->dev_replace.rwsem);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 1 lock held by btrfs/2326:
  #0: ffff88810f215c98 (&fs_info->dev_replace.rwsem){++++}-{3:3}, at: btrfs_map_block+0x39f/0x2250

 stack backtrace:
 CPU: 1 UID: 0 PID: 2326 Comm: btrfs Not tainted 6.11.0-rc3-btrfs-for-next #599
 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
 Call Trace:
  <TASK>
  dump_stack_lvl+0x5b/0x80
  __lock_acquire+0x2798/0x69d0
  ? __pfx___lock_acquire+0x10/0x10
  ? __pfx___lock_acquire+0x10/0x10
  lock_acquire+0x19d/0x4a0
  ? btrfs_map_block+0x39f/0x2250
  ? __pfx_lock_acquire+0x10/0x10
  ? find_held_lock+0x2d/0x110
  ? lock_is_held_type+0x8f/0x100
  down_read+0x8e/0x440
  ? btrfs_map_block+0x39f/0x2250
  ? __pfx_down_read+0x10/0x10
  ? do_raw_read_unlock+0x44/0x70
  ? _raw_read_unlock+0x23/0x40
  btrfs_map_block+0x39f/0x2250
  ? btrfs_dev_replace_by_ioctl+0xd69/0x1d00
  ? btrfs_bio_counter_inc_blocked+0xd9/0x2e0
  ? __kasan_slab_alloc+0x6e/0x70
  ? __pfx_btrfs_map_block+0x10/0x10
  ? __pfx_btrfs_bio_counter_inc_blocked+0x10/0x10
  ? kmem_cache_alloc_noprof+0x1f2/0x300
  ? mempool_alloc_noprof+0xed/0x2b0
  btrfs_submit_chunk+0x28d/0x17e0
  ? __pfx_btrfs_submit_chunk+0x10/0x10
  ? bvec_alloc+0xd7/0x1b0
  ? bio_add_folio+0x171/0x270
  ? __pfx_bio_add_folio+0x10/0x10
  ? __kasan_check_read+0x20/0x20
  btrfs_submit_bio+0x37/0x80
  read_extent_buffer_pages+0x3df/0x6c0
  btrfs_read_extent_buffer+0x13e/0x5f0
  read_tree_block+0x81/0xe0
  read_block_for_search+0x4bd/0x7a0
  ? __pfx_read_block_for_search+0x10/0x10
  btrfs_search_slot+0x78d/0x2720
  ? __pfx_btrfs_search_slot+0x10/0x10
  ? lock_is_held_type+0x8f/0x100
  ? kasan_save_track+0x14/0x30
  ? __kasan_slab_alloc+0x6e/0x70
  ? kmem_cache_alloc_noprof+0x1f2/0x300
  btrfs_get_raid_extent_offset+0x181/0x820
  ? __pfx_lock_acquire+0x10/0x10
  ? __pfx_btrfs_get_raid_extent_offset+0x10/0x10
  ? down_read+0x194/0x440
  ? __pfx_down_read+0x10/0x10
  ? do_raw_read_unlock+0x44/0x70
  ? _raw_read_unlock+0x23/0x40
  btrfs_map_block+0x5b5/0x2250
  ? __pfx_btrfs_map_block+0x10/0x10
  scrub_submit_initial_read+0x8fe/0x11b0
  ? __pfx_scrub_submit_initial_read+0x10/0x10
  submit_initial_group_read+0x161/0x3a0
  ? lock_release+0x20e/0x710
  ? __pfx_submit_initial_group_read+0x10/0x10
  ? __pfx_lock_release+0x10/0x10
  scrub_simple_mirror.isra.0+0x3eb/0x580
  scrub_stripe+0xe4d/0x1440
  ? lock_release+0x20e/0x710
  ? __pfx_scrub_stripe+0x10/0x10
  ? __pfx_lock_release+0x10/0x10
  ? do_raw_read_unlock+0x44/0x70
  ? _raw_read_unlock+0x23/0x40
  scrub_chunk+0x257/0x4a0
  scrub_enumerate_chunks+0x64c/0xf70
  ? __mutex_unlock_slowpath+0x147/0x5f0
  ? __pfx_scrub_enumerate_chunks+0x10/0x10
  ? bit_wait_timeout+0xb0/0x170
  ? __up_read+0x189/0x700
  ? scrub_workers_get+0x231/0x300
  ? up_write+0x490/0x4f0
  btrfs_scrub_dev+0x52e/0xcd0
  ? create_pending_snapshots+0x230/0x250
  ? __pfx_btrfs_scrub_dev+0x10/0x10
  btrfs_dev_replace_by_ioctl+0xd69/0x1d00
  ? lock_acquire+0x19d/0x4a0
  ? __pfx_btrfs_dev_replace_by_ioctl+0x10/0x10
  ? lock_release+0x20e/0x710
  ? btrfs_ioctl+0xa09/0x74f0
  ? __pfx_lock_release+0x10/0x10
  ? do_raw_spin_lock+0x11e/0x240
  ? __pfx_do_raw_spin_lock+0x10/0x10
  btrfs_ioctl+0xa14/0x74f0
  ? lock_acquire+0x19d/0x4a0
  ? find_held_lock+0x2d/0x110
  ? __pfx_btrfs_ioctl+0x10/0x10
  ? lock_release+0x20e/0x710
  ? do_sigaction+0x3f0/0x860
  ? __pfx_do_vfs_ioctl+0x10/0x10
  ? do_raw_spin_lock+0x11e/0x240
  ? lockdep_hardirqs_on_prepare+0x270/0x3e0
  ? _raw_spin_unlock_irq+0x28/0x50
  ? do_sigaction+0x3f0/0x860
  ? __pfx_do_sigaction+0x10/0x10
  ? __x64_sys_rt_sigaction+0x18e/0x1e0
  ? __pfx___x64_sys_rt_sigaction+0x10/0x10
  ? __x64_sys_close+0x7c/0xd0
  __x64_sys_ioctl+0x137/0x190
  do_syscall_64+0x71/0x140
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
 RIP: 0033:0x7f0bd1114f9b
 Code: Unable to access opcode bytes at 0x7f0bd1114f71.
 RSP: 002b:00007ffc8a8c3130 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f0bd1114f9b
 RDX: 00007ffc8a8c35e0 RSI: 00000000ca289435 RDI: 0000000000000003
 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000007
 R10: 0000000000000008 R11: 0000000000000246 R12: 00007ffc8a8c6c85
 R13: 00000000398e72a0 R14: 0000000000004361 R15: 0000000000000004
  </TASK>

This happens because on RAID stripe-tree filesystems we recurse back into
btrfs_map_block() on scrub to perform the logical to device physical
mapping.

But as the device replace task is already holding the dev_replace::rwsem
we deadlock.

So don't take the dev_replace::rwsem in case our task is the task performing
the device replace.

Suggested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2024-12-14 19:59:58 +01:00
arch s390/cpum_sf: Handle CPU hotplug remove during sampling 2024-12-14 19:59:58 +01:00
block block, bfq: fix bfqq uaf in bfq_limit_depth() 2024-12-09 10:33:00 +01:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: pcrypt - Call crypto layer directly when padata_do_parallel() return -EBUSY 2024-12-09 10:31:48 +01:00
Documentation zram: split memory-tracking and ac-time tracking 2024-12-14 19:59:44 +01:00
drivers mmc: core: Further prevent card detect during shutdown 2024-12-14 19:59:57 +01:00
fs btrfs: don't take dev_replace rwsem on task already holding it 2024-12-14 19:59:58 +01:00
include epoll: annotate racy check 2024-12-14 19:59:58 +01:00
init Compiler Attributes: disable __counted_by for clang < 19.1.3 2024-12-09 10:32:46 +01:00
io_uring io_uring: fix possible deadlock in io_register_iowq_max_workers() 2024-11-17 15:08:58 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-09 10:32:54 +01:00
kernel bpf: fix OOB devmap writes when deleting elements 2024-12-14 19:59:56 +01:00
lib lib: stackinit: hide never-taken branch from compiler 2024-12-14 19:59:57 +01:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm kasan: make report_lock a raw spinlock 2024-12-14 19:59:57 +01:00
net xsk: fix OOB map writes when deleting elements 2024-12-14 19:59:57 +01:00
rust rust: macros: fix documentation of the paste! macro 2024-12-09 10:32:25 +01:00
samples bpf: Fix the xdp_adjust_tail sample prog issue 2024-12-09 10:32:02 +01:00
scripts modpost: Add .irqentry.text to OTHER_SECTIONS 2024-12-14 19:59:56 +01:00
security apparmor: test: Fix memory leak for aa_unpack_strdup() 2024-12-09 10:32:45 +01:00
sound ALSA: hda/realtek: Add support for Samsung Galaxy Book3 360 (NP730QFG) 2024-12-14 19:59:53 +01:00
tools kselftest/arm64: Log fp-stress child startup errors to stdout 2024-12-14 19:59:58 +01:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Use dedicated mutex to protect kvm_usage_count to avoid deadlock 2024-10-04 16:29:47 +02:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Remove *.orig pattern from .gitignore 2024-10-04 16:29:44 +02:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS membarrier: riscv: Add full memory barrier in switch_mm() 2024-09-12 11:11:45 +02:00
Makefile Linux 6.6.65 2024-12-11 16:13:43 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

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.