Pull btrfs fixes from David Sterba:

- scan block devices in non-exclusive mode to avoid temporary mkfs
failures

- fix race between quota disable and quota assign ioctls

- fix deadlock when aborting transaction during relocation with scrub

- ignore fiemap path cache when there are multiple paths for a node

* tag 'for-6.3-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: ignore fiemap path cache when there are multiple paths for a node
btrfs: fix deadlock when aborting transaction during relocation with scrub
btrfs: scan device in non-exclusive mode
btrfs: fix race between quota disable and quota assign ioctls

This reverts commit a837e5161cff, which broke probing of the venus
driver, at least on the SC7180 SoC HP X2 Chromebook:

qcom-venus aa00000.video-codec: Adding to iommu group 11
qcom-venus aa00000.video-codec: non legacy binding
qcom-venus aa00000.video-codec: failed to reset venus core
qcom-venus: probe of aa00000.video-codec failed with error -110

Matthias Kaehlcke also reported that the same change caused a regression
in SC7180 and sc7280, that prevents AOSS from entering sleep mode during
system suspend. So let's revert this commit for now to fix both issues.

Fixes: a837e5161cff ("venus: firmware: Correct non-pix start and end addresses")
Reported-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

During fiemap, when walking backreferences to determine if a b+tree
node/leaf is shared, we may find a tree block (leaf or node) for which
two parents were added to the references ulist. This happens if we get
for example one direct ref (shared tree block ref) and one indirect ref
(non-shared tree block ref) for the tree block at the current level,
which can happen during relocation.

In that case the fiemap path cache can not be used since it's meant for
a single path, with one tree block at each possible level, so having
multiple references for a tree block at any level may result in getting
the level counter exceed BTRFS_MAX_LEVEL and eventually trigger the
warning:

WARN_ON_ONCE(level >= BTRFS_MAX_LEVEL)

at lookup_backref_shared_cache() and at store_backref_shared_cache().
This is harmless since the code ignores any level >= BTRFS_MAX_LEVEL, the
warning is there just to catch any unexpected case like the one described
above. However if a user finds this it may be scary and get reported.

So just ignore the path cache once we find a tree block for which there
are more than one reference, which is the less common case, and update
the cache with the sharedness check result for all levels below the level
for which we found multiple references.

Reported-by: Jarno Pelkonen <jarno.pelkonen@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CAKv8qLmDNAGJGCtsevxx_VZ_YOvvs1L83iEJkTgyA4joJertng@mail.gmail.com/
Fixes: 12a824dc67a6 ("btrfs: speedup checking for extent sharedness during fiemap")
CC: stable@vger.kernel.org # 6.1+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Pull driver core fixes from Greg KH:
"Here are three small changes for 6.3-rc5 semi-related to driver core
stuff:

- documentation update where we move the security_bugs file to a more
relevant location.

- mdt/spi-nor debugfs memory leak fix that's been floating around for
a long time and acked by the maintainer

- cacheinfo bugfix for a regression in 6.3-rc1

All have been in linux-next with no reported problems"

* tag 'driver-core-6.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
cacheinfo: Fix LLC is not exported through sysfs
Documentation/security-bugs: move from admin-guide/ to process/
mtd: spi-nor: fix memory leak when using debugfs_lookup()

Before relocating a block group we pause scrub, then do the relocation and
then unpause scrub. The relocation process requires starting and committing
a transaction, and if we have a failure in the critical section of the
transaction commit path (transaction state >= TRANS_STATE_COMMIT_START),
we will deadlock if there is a paused scrub.

That results in stack traces like the following:

[42.479] BTRFS info (device sdc): relocating block group 53876686848 flags metadata|raid6
[42.936] BTRFS warning (device sdc): Skipping commit of aborted transaction.
[42.936] ------------[ cut here ]------------
[42.936] BTRFS: Transaction aborted (error -28)
[42.936] WARNING: CPU: 11 PID: 346822 at fs/btrfs/transaction.c:1977 btrfs_commit_transaction+0xcc8/0xeb0 [btrfs]
[42.936] Modules linked in: dm_flakey dm_mod loop btrfs (...)
[42.936] CPU: 11 PID: 346822 Comm: btrfs Tainted: G W 6.3.0-rc2-btrfs-next-127+ #1
[42.936] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[42.936] RIP: 0010:btrfs_commit_transaction+0xcc8/0xeb0 [btrfs]
[42.936] Code: ff ff 45 8b (...)
[42.936] RSP: 0018:ffffb58649633b48 EFLAGS: 00010282
[42.936] RAX: 0000000000000000 RBX: ffff8be6ef4d5bd8 RCX: 0000000000000000
[42.936] RDX: 0000000000000002 RSI: ffffffffb35e7782 RDI: 00000000ffffffff
[42.936] RBP: ffff8be6ef4d5c98 R08: 0000000000000000 R09: ffffb586496339e8
[42.936] R10: 0000000000000001 R11: 0000000000000001 R12: ffff8be6d38c7c00
[42.936] R13: 00000000ffffffe4 R14: ffff8be6c268c000 R15: ffff8be6ef4d5cf0
[42.936] FS: 00007f381a82b340(0000) GS:ffff8beddfcc0000(0000) knlGS:0000000000000000
[42.936] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[42.936] CR2: 00007f1e35fb7638 CR3: 0000000117680006 CR4: 0000000000370ee0
[42.936] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[42.936] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[42.936] Call Trace:
[42.936] <TASK>
[42.936] ? start_transaction+0xcb/0x610 [btrfs]
[42.936] prepare_to_relocate+0x111/0x1a0 [btrfs]
[42.936] relocate_block_group+0x57/0x5d0 [btrfs]
[42.936] ? btrfs_wait_nocow_writers+0x25/0xb0 [btrfs]
[42.936] btrfs_relocate_block_group+0x248/0x3c0 [btrfs]
[42.936] ? __pfx_autoremove_wake_function+0x10/0x10
[42.936] btrfs_relocate_chunk+0x3b/0x150 [btrfs]
[42.936] btrfs_balance+0x8ff/0x11d0 [btrfs]
[42.936] ? __kmem_cache_alloc_node+0x14a/0x410
[42.936] btrfs_ioctl+0x2334/0x32c0 [btrfs]
[42.937] ? mod_objcg_state+0xd2/0x360
[42.937] ? refill_obj_stock+0xb0/0x160
[42.937] ? seq_release+0x25/0x30
[42.937] ? __rseq_handle_notify_resume+0x3b5/0x4b0
[42.937] ? percpu_counter_add_batch+0x2e/0xa0
[42.937] ? __x64_sys_ioctl+0x88/0xc0
[42.937] __x64_sys_ioctl+0x88/0xc0
[42.937] do_syscall_64+0x38/0x90
[42.937] entry_SYSCALL_64_after_hwframe+0x72/0xdc
[42.937] RIP: 0033:0x7f381a6ffe9b
[42.937] Code: 00 48 89 44 24 (...)
[42.937] RSP: 002b:00007ffd45ecf060 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[42.937] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f381a6ffe9b
[42.937] RDX: 00007ffd45ecf150 RSI: 00000000c4009420 RDI: 0000000000000003
[42.937] RBP: 0000000000000003 R08: 0000000000000013 R09: 0000000000000000
[42.937] R10: 00007f381a60c878 R11: 0000000000000246 R12: 00007ffd45ed0423
[42.937] R13: 00007ffd45ecf150 R14: 0000000000000000 R15: 00007ffd45ecf148
[42.937] </TASK>
[42.937] ---[ end trace 0000000000000000 ]---
[42.937] BTRFS: error (device sdc: state A) in cleanup_transaction:1977: errno=-28 No space left
[59.196] INFO: task btrfs:346772 blocked for more than 120 seconds.
[59.196] Tainted: G W 6.3.0-rc2-btrfs-next-127+ #1
[59.196] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[59.196] task:btrfs state:D stack:0 pid:346772 ppid:1 flags:0x00004002
[59.196] Call Trace:
[59.196] <TASK>
[59.196] __schedule+0x392/0xa70
[59.196] ? __pv_queued_spin_lock_slowpath+0x165/0x370
[59.196] schedule+0x5d/0xd0
[59.196] __scrub_blocked_if_needed+0x74/0xc0 [btrfs]
[59.197] ? __pfx_autoremove_wake_function+0x10/0x10
[59.197] scrub_pause_off+0x21/0x50 [btrfs]
[59.197] scrub_simple_mirror+0x1c7/0x950 [btrfs]
[59.197] ? scrub_parity_put+0x1a5/0x1d0 [btrfs]
[59.198] ? __pfx_autoremove_wake_function+0x10/0x10
[59.198] scrub_stripe+0x20d/0x740 [btrfs]
[59.198] scrub_chunk+0xc4/0x130 [btrfs]
[59.198] scrub_enumerate_chunks+0x3e4/0x7a0 [btrfs]
[59.198] ? __pfx_autoremove_wake_function+0x10/0x10
[59.198] btrfs_scrub_dev+0x236/0x6a0 [btrfs]
[59.199] ? btrfs_ioctl+0xd97/0x32c0 [btrfs]
[59.199] ? _copy_from_user+0x7b/0x80
[59.199] btrfs_ioctl+0xde1/0x32c0 [btrfs]
[59.199] ? refill_stock+0x33/0x50
[59.199] ? should_failslab+0xa/0x20
[59.199] ? kmem_cache_alloc_node+0x151/0x460
[59.199] ? alloc_io_context+0x1b/0x80
[59.199] ? preempt_count_add+0x70/0xa0
[59.199] ? __x64_sys_ioctl+0x88/0xc0
[59.199] __x64_sys_ioctl+0x88/0xc0
[59.199] do_syscall_64+0x38/0x90
[59.199] entry_SYSCALL_64_after_hwframe+0x72/0xdc
[59.199] RIP: 0033:0x7f82ffaffe9b
[59.199] RSP: 002b:00007f82ff9fcc50 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[59.199] RAX: ffffffffffffffda RBX: 000055b191e36310 RCX: 00007f82ffaffe9b
[59.199] RDX: 000055b191e36310 RSI: 00000000c400941b RDI: 0000000000000003
[59.199] RBP: 0000000000000000 R08: 00007fff1575016f R09: 0000000000000000
[59.199] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f82ff9fd640
[59.199] R13: 000000000000006b R14: 00007f82ffa87580 R15: 0000000000000000
[59.199] </TASK>
[59.199] INFO: task btrfs:346773 blocked for more than 120 seconds.
[59.200] Tainted: G W 6.3.0-rc2-btrfs-next-127+ #1
[59.200] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[59.201] task:btrfs state:D stack:0 pid:346773 ppid:1 flags:0x00004002
[59.201] Call Trace:
[59.201] <TASK>
[59.201] __schedule+0x392/0xa70
[59.201] ? __pv_queued_spin_lock_slowpath+0x165/0x370
[59.201] schedule+0x5d/0xd0
[59.201] __scrub_blocked_if_needed+0x74/0xc0 [btrfs]
[59.201] ? __pfx_autoremove_wake_function+0x10/0x10
[59.201] scrub_pause_off+0x21/0x50 [btrfs]
[59.202] scrub_simple_mirror+0x1c7/0x950 [btrfs]
[59.202] ? scrub_parity_put+0x1a5/0x1d0 [btrfs]
[59.202] ? __pfx_autoremove_wake_function+0x10/0x10
[59.202] scrub_stripe+0x20d/0x740 [btrfs]
[59.202] scrub_chunk+0xc4/0x130 [btrfs]
[59.203] scrub_enumerate_chunks+0x3e4/0x7a0 [btrfs]
[59.203] ? __pfx_autoremove_wake_function+0x10/0x10
[59.203] btrfs_scrub_dev+0x236/0x6a0 [btrfs]
[59.203] ? btrfs_ioctl+0xd97/0x32c0 [btrfs]
[59.203] ? _copy_from_user+0x7b/0x80
[59.203] btrfs_ioctl+0xde1/0x32c0 [btrfs]
[59.204] ? should_failslab+0xa/0x20
[59.204] ? kmem_cache_alloc_node+0x151/0x460
[59.204] ? alloc_io_context+0x1b/0x80
[59.204] ? preempt_count_add+0x70/0xa0
[59.204] ? __x64_sys_ioctl+0x88/0xc0
[59.204] __x64_sys_ioctl+0x88/0xc0
[59.204] do_syscall_64+0x38/0x90
[59.204] entry_SYSCALL_64_after_hwframe+0x72/0xdc
[59.204] RIP: 0033:0x7f82ffaffe9b
[59.204] RSP: 002b:00007f82ff1fbc50 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[59.204] RAX: ffffffffffffffda RBX: 000055b191e36790 RCX: 00007f82ffaffe9b
[59.204] RDX: 000055b191e36790 RSI: 00000000c400941b RDI: 0000000000000003
[59.204] RBP: 0000000000000000 R08: 00007fff1575016f R09: 0000000000000000
[59.204] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f82ff1fc640
[59.204] R13: 000000000000006b R14: 00007f82ffa87580 R15: 0000000000000000
[59.204] </TASK>
[59.204] INFO: task btrfs:346774 blocked for more than 120 seconds.
[59.205] Tainted: G W 6.3.0-rc2-btrfs-next-127+ #1
[59.205] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[59.206] task:btrfs state:D stack:0 pid:346774 ppid:1 flags:0x00004002
[59.206] Call Trace:
[59.206] <TASK>
[59.206] __schedule+0x392/0xa70
[59.206] schedule+0x5d/0xd0
[59.206] __scrub_blocked_if_needed+0x74/0xc0 [btrfs]
[59.206] ? __pfx_autoremove_wake_function+0x10/0x10
[59.206] scrub_pause_off+0x21/0x50 [btrfs]
[59.207] scrub_simple_mirror+0x1c7/0x950 [btrfs]
[59.207] ? scrub_parity_put+0x1a5/0x1d0 [btrfs]
[59.207] ? __pfx_autoremove_wake_function+0x10/0x10
[59.207] scrub_stripe+0x20d/0x740 [btrfs]
[59.208] scrub_chunk+0xc4/0x130 [btrfs]
[59.208] scrub_enumerate_chunks+0x3e4/0x7a0 [btrfs]
[59.208] ? __mutex_unlock_slowpath.isra.0+0x9a/0x120
[59.208] btrfs_scrub_dev+0x236/0x6a0 [btrfs]
[59.208] ? btrfs_ioctl+0xd97/0x32c0 [btrfs]
[59.209] ? _copy_from_user+0x7b/0x80
[59.209] btrfs_ioctl+0xde1/0x32c0 [btrfs]
[59.209] ? should_failslab+0xa/0x20
[59.209] ? kmem_cache_alloc_node+0x151/0x460
[59.209] ? alloc_io_context+0x1b/0x80
[59.209] ? preempt_count_add+0x70/0xa0
[59.209] ? __x64_sys_ioctl+0x88/0xc0
[59.209] __x64_sys_ioctl+0x88/0xc0
[59.209] do_syscall_64+0x38/0x90
[59.209] entry_SYSCALL_64_after_hwframe+0x72/0xdc
[59.209] RIP: 0033:0x7f82ffaffe9b
[59.209] RSP: 002b:00007f82fe9fac50 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[59.209] RAX: ffffffffffffffda RBX: 000055b191e36c10 RCX: 00007f82ffaffe9b
[59.209] RDX: 000055b191e36c10 RSI: 00000000c400941b RDI: 0000000000000003
[59.209] RBP: 0000000000000000 R08: 00007fff1575016f R09: 0000000000000000
[59.209] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f82fe9fb640
[59.209] R13: 000000000000006b R14: 00007f82ffa87580 R15: 0000000000000000
[59.209] </TASK>
[59.209] INFO: task btrfs:346775 blocked for more than 120 seconds.
[59.210] Tainted: G W 6.3.0-rc2-btrfs-next-127+ #1
[59.210] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[59.211] task:btrfs state:D stack:0 pid:346775 ppid:1 flags:0x00004002
[59.211] Call Trace:
[59.211] <TASK>
[59.211] __schedule+0x392/0xa70
[59.211] schedule+0x5d/0xd0
[59.211] __scrub_blocked_if_needed+0x74/0xc0 [btrfs]
[59.211] ? __pfx_autoremove_wake_function+0x10/0x10
[59.211] scrub_pause_off+0x21/0x50 [btrfs]
[59.212] scrub_simple_mirror+0x1c7/0x950 [btrfs]
[59.212] ? scrub_parity_put+0x1a5/0x1d0 [btrfs]
[59.212] ? __pfx_autoremove_wake_function+0x10/0x10
[59.212] scrub_stripe+0x20d/0x740 [btrfs]
[59.213] scrub_chunk+0xc4/0x130 [btrfs]
[59.213] scrub_enumerate_chunks+0x3e4/0x7a0 [btrfs]
[59.213] ? __mutex_unlock_slowpath.isra.0+0x9a/0x120
[59.213] btrfs_scrub_dev+0x236/0x6a0 [btrfs]
[59.213] ? btrfs_ioctl+0xd97/0x32c0 [btrfs]
[59.214] ? _copy_from_user+0x7b/0x80
[59.214] btrfs_ioctl+0xde1/0x32c0 [btrfs]
[59.214] ? should_failslab+0xa/0x20
[59.214] ? kmem_cache_alloc_node+0x151/0x460
[59.214] ? alloc_io_context+0x1b/0x80
[59.214] ? preempt_count_add+0x70/0xa0
[59.214] ? __x64_sys_ioctl+0x88/0xc0
[59.214] __x64_sys_ioctl+0x88/0xc0
[59.214] do_syscall_64+0x38/0x90
[59.214] entry_SYSCALL_64_after_hwframe+0x72/0xdc
[59.214] RIP: 0033:0x7f82ffaffe9b
[59.214] RSP: 002b:00007f82fe1f9c50 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[59.214] RAX: ffffffffffffffda RBX: 000055b191e37090 RCX: 00007f82ffaffe9b
[59.214] RDX: 000055b191e37090 RSI: 00000000c400941b RDI: 0000000000000003
[59.214] RBP: 0000000000000000 R08: 00007fff1575016f R09: 0000000000000000
[59.214] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f82fe1fa640
[59.214] R13: 000000000000006b R14: 00007f82ffa87580 R15: 0000000000000000
[59.214] </TASK>
[59.214] INFO: task btrfs:346776 blocked for more than 120 seconds.
[59.215] Tainted: G W 6.3.0-rc2-btrfs-next-127+ #1
[59.216] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[59.217] task:btrfs state:D stack:0 pid:346776 ppid:1 flags:0x00004002
[59.217] Call Trace:
[59.217] <TASK>
[59.217] __schedule+0x392/0xa70
[59.217] ? __pv_queued_spin_lock_slowpath+0x165/0x370
[59.217] schedule+0x5d/0xd0
[59.217] __scrub_blocked_if_needed+0x74/0xc0 [btrfs]
[59.217] ? __pfx_autoremove_wake_function+0x10/0x10
[59.217] scrub_pause_off+0x21/0x50 [btrfs]
[59.217] scrub_simple_mirror+0x1c7/0x950 [btrfs]
[59.217] ? scrub_parity_put+0x1a5/0x1d0 [btrfs]
[59.218] ? __pfx_autoremove_wake_function+0x10/0x10
[59.218] scrub_stripe+0x20d/0x740 [btrfs]
[59.218] scrub_chunk+0xc4/0x130 [btrfs]
[59.218] scrub_enumerate_chunks+0x3e4/0x7a0 [btrfs]
[59.219] ? __pfx_autoremove_wake_function+0x10/0x10
[59.219] btrfs_scrub_dev+0x236/0x6a0 [btrfs]
[59.219] ? btrfs_ioctl+0xd97/0x32c0 [btrfs]
[59.219] ? _copy_from_user+0x7b/0x80
[59.219] btrfs_ioctl+0xde1/0x32c0 [btrfs]
[59.219] ? should_failslab+0xa/0x20
[59.219] ? kmem_cache_alloc_node+0x151/0x460
[59.219] ? alloc_io_context+0x1b/0x80
[59.219] ? preempt_count_add+0x70/0xa0
[59.219] ? __x64_sys_ioctl+0x88/0xc0
[59.219] __x64_sys_ioctl+0x88/0xc0
[59.219] do_syscall_64+0x38/0x90
[59.219] entry_SYSCALL_64_after_hwframe+0x72/0xdc
[59.219] RIP: 0033:0x7f82ffaffe9b
[59.219] RSP: 002b:00007f82fd9f8c50 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[59.219] RAX: ffffffffffffffda RBX: 000055b191e37510 RCX: 00007f82ffaffe9b
[59.219] RDX: 000055b191e37510 RSI: 00000000c400941b RDI: 0000000000000003
[59.219] RBP: 0000000000000000 R08: 00007fff1575016f R09: 0000000000000000
[59.219] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f82fd9f9640
[59.219] R13: 000000000000006b R14: 00007f82ffa87580 R15: 0000000000000000
[59.219] </TASK>
[59.219] INFO: task btrfs:346822 blocked for more than 120 seconds.
[59.220] Tainted: G W 6.3.0-rc2-btrfs-next-127+ #1
[59.221] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[59.222] task:btrfs state:D stack:0 pid:346822 ppid:1 flags:0x00004002
[59.222] Call Trace:
[59.222] <TASK>
[59.222] __schedule+0x392/0xa70
[59.222] schedule+0x5d/0xd0
[59.222] btrfs_scrub_cancel+0x91/0x100 [btrfs]
[59.222] ? __pfx_autoremove_wake_function+0x10/0x10
[59.222] btrfs_commit_transaction+0x572/0xeb0 [btrfs]
[59.223] ? start_transaction+0xcb/0x610 [btrfs]
[59.223] prepare_to_relocate+0x111/0x1a0 [btrfs]
[59.223] relocate_block_group+0x57/0x5d0 [btrfs]
[59.223] ? btrfs_wait_nocow_writers+0x25/0xb0 [btrfs]
[59.223] btrfs_relocate_block_group+0x248/0x3c0 [btrfs]
[59.224] ? __pfx_autoremove_wake_function+0x10/0x10
[59.224] btrfs_relocate_chunk+0x3b/0x150 [btrfs]
[59.224] btrfs_balance+0x8ff/0x11d0 [btrfs]
[59.224] ? __kmem_cache_alloc_node+0x14a/0x410
[59.224] btrfs_ioctl+0x2334/0x32c0 [btrfs]
[59.225] ? mod_objcg_state+0xd2/0x360
[59.225] ? refill_obj_stock+0xb0/0x160
[59.225] ? seq_release+0x25/0x30
[59.225] ? __rseq_handle_notify_resume+0x3b5/0x4b0
[59.225] ? percpu_counter_add_batch+0x2e/0xa0
[59.225] ? __x64_sys_ioctl+0x88/0xc0
[59.225] __x64_sys_ioctl+0x88/0xc0
[59.225] do_syscall_64+0x38/0x90
[59.225] entry_SYSCALL_64_after_hwframe+0x72/0xdc
[59.225] RIP: 0033:0x7f381a6ffe9b
[59.225] RSP: 002b:00007ffd45ecf060 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[59.225] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f381a6ffe9b
[59.225] RDX: 00007ffd45ecf150 RSI: 00000000c4009420 RDI: 0000000000000003
[59.225] RBP: 0000000000000003 R08: 0000000000000013 R09: 0000000000000000
[59.225] R10: 00007f381a60c878 R11: 0000000000000246 R12: 00007ffd45ed0423
[59.225] R13: 00007ffd45ecf150 R14: 0000000000000000 R15: 00007ffd45ecf148
[59.225] </TASK>

What happens is the following:

1) A scrub is running, so fs_info->scrubs_running is 1;

2) Task A starts block group relocation, and at btrfs_relocate_chunk() it
pauses scrub by calling btrfs_scrub_pause(). That increments
fs_info->scrub_pause_req from 0 to 1 and waits for the scrub task to
pause (for fs_info->scrubs_paused to be == to fs_info->scrubs_running);

3) The scrub task pauses at scrub_pause_off(), waiting for
fs_info->scrub_pause_req to decrease to 0;

4) Task A then enters btrfs_relocate_block_group(), and down that call
chain we start a transaction and then attempt to commit it;

5) When task A calls btrfs_commit_transaction(), it either will do the
commit itself or wait for some other task that already started the
commit of the transaction - it doesn't matter which case;

6) The transaction commit enters state TRANS_STATE_COMMIT_START;

7) An error happens during the transaction commit, like -ENOSPC when
running delayed refs or delayed items for example;

8) This results in calling transaction.c:cleanup_transaction(), where
we call btrfs_scrub_cancel(), incrementing fs_info->scrub_cancel_req
from 0 to 1, and blocking this task waiting for fs_info->scrubs_running
to decrease to 0;

9) From this point on, both the transaction commit and the scrub task
hang forever:

1) The transaction commit is waiting for fs_info->scrubs_running to
be decreased to 0;

2) The scrub task is at scrub_pause_off() waiting for
fs_info->scrub_pause_req to decrease to 0 - so it can not proceed
to stop the scrub and decrement fs_info->scrubs_running from 0 to 1.

Therefore resulting in a deadlock.

Fix this by having cleanup_transaction(), called if a transaction commit
fails, not call btrfs_scrub_cancel() if relocation is in progress, and
having btrfs_relocate_block_group() call btrfs_scrub_cancel() instead if
the relocation failed and a transaction abort happened.

This was triggered with btrfs/061 from fstests.

Fixes: 55e3a601c81c ("btrfs: Fix data checksum error cause by replace with io-load.")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Pull powerpc fixes from Michael Ellerman:

- Fix a false positive warning in __pte_needs_flush() (with DEBUG_VM=y)

- Fix oops when a PF_IO_WORKER thread tries to core dump

- Don't try to reconfigure VAS when it's disabled

Thanks to Benjamin Gray, Haren Myneni, Jens Axboe, Nathan Lynch, and
Russell Currey.

* tag 'powerpc-6.3-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/pseries/vas: Ignore VAS update for DLPAR if copy/paste is not enabled
powerpc: Don't try to copy PPR for task with NULL pt_regs
powerpc/64s: Fix __pte_needs_flush() false positive warning

After entering 6.3-rc1 the LLC cacheinfo is not exported on our ACPI
based arm64 server. This is because the LLC cacheinfo is partly reset
when secondary CPUs boot up. On arm64 the primary cpu will allocate
and setup cacheinfo:
init_cpu_topology()
for_each_possible_cpu()
fetch_cache_info() // Allocate cacheinfo and init levels
detect_cache_attributes()
cache_shared_cpu_map_setup()
if (!last_level_cache_is_valid()) // not valid, setup LLC
cache_setup_properties() // setup LLC

On secondary CPU boot up:
detect_cache_attributes()
populate_cache_leaves()
get_cache_type() // Get cache type from clidr_el1,
// for LLC type=CACHE_TYPE_NOCACHE
cache_shared_cpu_map_setup()
if (!last_level_cache_is_valid()) // Valid and won't go to this branch,
// leave LLC's type=CACHE_TYPE_NOCACHE

The last_level_cache_is_valid() use cacheinfo->{attributes, fw_token} to
test it's valid or not, but populate_cache_leaves() will only reset
LLC's type, so we won't try to re-setup LLC's type and leave it
CACHE_TYPE_NOCACHE and won't export it through sysfs.

This patch tries to fix this by not re-populating the cache leaves if
the LLC is valid.

Fixes: 5944ce092b97 ("arch_topology: Build cacheinfo from primary CPU")
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20230328114915.33340-1-yangyicong@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This fixes mkfs/mount/check failures due to race with systemd-udevd
scan.

During the device scan initiated by systemd-udevd, other user space
EXCL operations such as mkfs, mount, or check may get blocked and result
in a "Device or resource busy" error. This is because the device
scan process opens the device with the EXCL flag in the kernel.

Two reports were received:

- btrfs/179 test case, where the fsck command failed with the -EBUSY
error

- LTP pwritev03 test case, where mkfs.vfs failed with
the -EBUSY error, when mkfs.vfs tried to overwrite old btrfs filesystem
on the device.

In both cases, fsck and mkfs (respectively) were racing with a
systemd-udevd device scan, and systemd-udevd won, resulting in the
-EBUSY error for fsck and mkfs.

Reproducing the problem has been difficult because there is a very
small window during which these userspace threads can race to
acquire the exclusive device open. Even on the system where the problem
was observed, the problem occurrences were anywhere between 10 to 400
iterations and chances of reproducing decreases with debug printk()s.

However, an exclusive device open is unnecessary for the scan process,
as there are no write operations on the device during scan. Furthermore,
during the mount process, the superblock is re-read in the below
function call chain:

btrfs_mount_root
btrfs_open_devices
open_fs_devices
btrfs_open_one_device
btrfs_get_bdev_and_sb

So, to fix this issue, removes the FMODE_EXCL flag from the scan
operation, and add a comment.

The case where mkfs may still write to the device and a scan is running,
the btrfs signature is not written at that time so scan will not
recognize such device.

Reported-by: Sherry Yang <sherry.yang@oracle.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202303170839.fdf23068-oliver.sang@intel.com
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Pull cifs client fixes from Steve French:
"Four cifs/smb3 client (reconnect and DFS related) fixes, including two
for stable:

- DFS oops fix

- DFS reconnect recursion fix

- An SMB1 parallel reconnect fix

- Trivial dead code removal in smb2_reconnect"

* tag '6.3-rc4-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
cifs: get rid of dead check in smb2_reconnect()
cifs: prevent infinite recursion in CIFSGetDFSRefer()
cifs: avoid races in parallel reconnects in smb1
cifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL

The hypervisor supports user-mode NX from Power10.

pseries_vas_dlpar_cpu() is called from lparcfg_write() to update VAS
windows for DLPAR event in shared processor mode and the kernel gets
-ENOTSUPP for HCALLs if the user-mode NX is not supported. The current
VAS implementation also supports only with Radix page tables. Whereas in
dedicated processor mode, pseries_vas_notifier() is registered only if
the copy/paste feature is enabled. So instead of displaying HCALL error
messages, update VAS capabilities if the copy/paste feature is
available.

This patch ignores updating VAS capabilities in pseries_vas_dlpar_cpu()
and returns success if the copy/paste feature is not enabled. Then
lparcfg_write() completes the processor DLPAR operations without any
failures.

Fixes: 2147783d6bf0 ("powerpc/pseries: Use lparcfg to reconfig VAS windows for DLPAR CPU")
Cc: stable@vger.kernel.org # v6.1+
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/1d0e727e7dbd9a28627ef08ca9df9c86a50175e2.camel@linux.ibm.com

Jiri Kosina, Jonathan Corbet, and Willy Tarreau all expressed a desire
to move this document under process/.

Create a new section for security issues in the index and group it with
embargoed-hardware-issues.

I'm doing this at the start of the series to make all the subsequent
changes show up in 'git blame'.

Existing references were updated using:

git grep -l security-bugs ':!Documentation/translations/' | xargs sed -i 's|admin-guide/security-bugs|process/security-bugs|g'
git grep -l security-bugs Documentation/translations/ | xargs sed -i 's|Documentation/admin-guide/security-bugs|Documentation/process/security-bugs|g'
git grep -l security-bugs Documentation/translations/ | xargs sed -i '/Original:/s|\.\./admin-guide/security-bugs|\.\./process/security-bugs|g'

Notably, the page is not moved in the translations (due to my lack of
knowledge of these languages), but the translations have been updated
to point to the new location of the original document where these
references exist.

Link: https://lore.kernel.org/all/nycvar.YFH.7.76.2206062326230.10851@cbobk.fhfr.pm/
Suggested-by: Jiri Kosina <jikos@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Cc: Hu Haowen <src.res@email.cn>
Cc: Federico Vaga <federico.vaga@vaga.pv.it>
Cc: Tsugikazu Shibata <tshibata@ab.jp.nec.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jeimi Lee <jamee.lee@samsung.com>
Cc: Carlos Bilbao <carlos.bilbao@amd.com>
Cc: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Carlos Bilbao <carlos.bilbao@amd.com>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Akira Yokosawa <akiyks@gmail.com>
Acked-by: Federico Vaga <federico.vaga@vaga.pv.it>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/20230305220010.20895-2-vegard.nossum@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The quota assign ioctl can currently run in parallel with a quota disable
ioctl call. The assign ioctl uses the quota root, while the disable ioctl
frees that root, and therefore we can have a use-after-free triggered in
the assign ioctl, leading to a trace like the following when KASAN is
enabled:

[672.723][T736] BUG: KASAN: slab-use-after-free in btrfs_search_slot+0x2962/0x2db0
[672.723][T736] Read of size 8 at addr ffff888022ec0208 by task btrfs_search_sl/27736
[672.724][T736]
[672.725][T736] CPU: 1 PID: 27736 Comm: btrfs_search_sl Not tainted 6.3.0-rc3 #37
[672.723][T736] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
[672.727][T736] Call Trace:
[672.728][T736] <TASK>
[672.728][T736] dump_stack_lvl+0xd9/0x150
[672.725][T736] print_report+0xc1/0x5e0
[672.720][T736] ? __virt_addr_valid+0x61/0x2e0
[672.727][T736] ? __phys_addr+0xc9/0x150
[672.725][T736] ? btrfs_search_slot+0x2962/0x2db0
[672.722][T736] kasan_report+0xc0/0xf0
[672.729][T736] ? btrfs_search_slot+0x2962/0x2db0
[672.724][T736] btrfs_search_slot+0x2962/0x2db0
[672.723][T736] ? fs_reclaim_acquire+0xba/0x160
[672.722][T736] ? split_leaf+0x13d0/0x13d0
[672.726][T736] ? rcu_is_watching+0x12/0xb0
[672.723][T736] ? kmem_cache_alloc+0x338/0x3c0
[672.722][T736] update_qgroup_status_item+0xf7/0x320
[672.724][T736] ? add_qgroup_rb+0x3d0/0x3d0
[672.739][T736] ? do_raw_spin_lock+0x12d/0x2b0
[672.730][T736] ? spin_bug+0x1d0/0x1d0
[672.737][T736] btrfs_run_qgroups+0x5de/0x840
[672.730][T736] ? btrfs_qgroup_rescan_worker+0xa70/0xa70
[672.738][T736] ? __del_qgroup_relation+0x4ba/0xe00
[672.738][T736] btrfs_ioctl+0x3d58/0x5d80
[672.735][T736] ? tomoyo_path_number_perm+0x16a/0x550
[672.737][T736] ? tomoyo_execute_permission+0x4a0/0x4a0
[672.731][T736] ? btrfs_ioctl_get_supported_features+0x50/0x50
[672.737][T736] ? __sanitizer_cov_trace_switch+0x54/0x90
[672.734][T736] ? do_vfs_ioctl+0x132/0x1660
[672.730][T736] ? vfs_fileattr_set+0xc40/0xc40
[672.730][T736] ? _raw_spin_unlock_irq+0x2e/0x50
[672.732][T736] ? sigprocmask+0xf2/0x340
[672.737][T736] ? __fget_files+0x26a/0x480
[672.732][T736] ? bpf_lsm_file_ioctl+0x9/0x10
[672.738][T736] ? btrfs_ioctl_get_supported_features+0x50/0x50
[672.736][T736] __x64_sys_ioctl+0x198/0x210
[672.736][T736] do_syscall_64+0x39/0xb0
[672.731][T736] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[672.739][T736] RIP: 0033:0x4556ad
[672.742][T736] </TASK>
[672.743][T736]
[672.748][T736] Allocated by task 27677:
[672.743][T736] kasan_save_stack+0x22/0x40
[672.741][T736] kasan_set_track+0x25/0x30
[672.741][T736] __kasan_kmalloc+0xa4/0xb0
[672.749][T736] btrfs_alloc_root+0x48/0x90
[672.746][T736] btrfs_create_tree+0x146/0xa20
[672.744][T736] btrfs_quota_enable+0x461/0x1d20
[672.743][T736] btrfs_ioctl+0x4a1c/0x5d80
[672.747][T736] __x64_sys_ioctl+0x198/0x210
[672.749][T736] do_syscall_64+0x39/0xb0
[672.744][T736] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[672.756][T736]
[672.757][T736] Freed by task 27677:
[672.759][T736] kasan_save_stack+0x22/0x40
[672.759][T736] kasan_set_track+0x25/0x30
[672.756][T736] kasan_save_free_info+0x2e/0x50
[672.751][T736] ____kasan_slab_free+0x162/0x1c0
[672.758][T736] slab_free_freelist_hook+0x89/0x1c0
[672.752][T736] __kmem_cache_free+0xaf/0x2e0
[672.752][T736] btrfs_put_root+0x1ff/0x2b0
[672.759][T736] btrfs_quota_disable+0x80a/0xbc0
[672.752][T736] btrfs_ioctl+0x3e5f/0x5d80
[672.756][T736] __x64_sys_ioctl+0x198/0x210
[672.753][T736] do_syscall_64+0x39/0xb0
[672.765][T736] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[672.769][T736]
[672.768][T736] The buggy address belongs to the object at ffff888022ec0000
[672.768][T736] which belongs to the cache kmalloc-4k of size 4096
[672.769][T736] The buggy address is located 520 bytes inside of
[672.769][T736] freed 4096-byte region [ffff888022ec0000, ffff888022ec1000)
[672.760][T736]
[672.764][T736] The buggy address belongs to the physical page:
[672.761][T736] page:ffffea00008bb000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x22ec0
[672.766][T736] head:ffffea00008bb000 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
[672.779][T736] flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
[672.770][T736] raw: 00fff00000010200 ffff888012842140 ffffea000054ba00 dead000000000002
[672.770][T736] raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
[672.771][T736] page dumped because: kasan: bad access detected
[672.778][T736] page_owner tracks the page as allocated
[672.777][T736] page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 88
[672.779][T736] get_page_from_freelist+0x119c/0x2d50
[672.779][T736] __alloc_pages+0x1cb/0x4a0
[672.776][T736] alloc_pages+0x1aa/0x270
[672.773][T736] allocate_slab+0x260/0x390
[672.771][T736] ___slab_alloc+0xa9a/0x13e0
[672.778][T736] __slab_alloc.constprop.0+0x56/0xb0
[672.771][T736] __kmem_cache_alloc_node+0x136/0x320
[672.789][T736] __kmalloc+0x4e/0x1a0
[672.783][T736] tomoyo_realpath_from_path+0xc3/0x600
[672.781][T736] tomoyo_path_perm+0x22f/0x420
[672.782][T736] tomoyo_path_unlink+0x92/0xd0
[672.780][T736] security_path_unlink+0xdb/0x150
[672.788][T736] do_unlinkat+0x377/0x680
[672.788][T736] __x64_sys_unlink+0xca/0x110
[672.789][T736] do_syscall_64+0x39/0xb0
[672.783][T736] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[672.784][T736] page last free stack trace:
[672.787][T736] free_pcp_prepare+0x4e5/0x920
[672.787][T736] free_unref_page+0x1d/0x4e0
[672.784][T736] __unfreeze_partials+0x17c/0x1a0
[672.797][T736] qlist_free_all+0x6a/0x180
[672.796][T736] kasan_quarantine_reduce+0x189/0x1d0
[672.797][T736] __kasan_slab_alloc+0x64/0x90
[672.793][T736] kmem_cache_alloc+0x17c/0x3c0
[672.799][T736] getname_flags.part.0+0x50/0x4e0
[672.799][T736] getname_flags+0x9e/0xe0
[672.792][T736] vfs_fstatat+0x77/0xb0
[672.791][T736] __do_sys_newlstat+0x84/0x100
[672.798][T736] do_syscall_64+0x39/0xb0
[672.796][T736] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[672.790][T736]
[672.791][T736] Memory state around the buggy address:
[672.799][T736] ffff888022ec0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[672.805][T736] ffff888022ec0180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[672.802][T736] >ffff888022ec0200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[672.809][T736] ^
[672.809][T736] ffff888022ec0280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[672.809][T736] ffff888022ec0300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Fix this by having the qgroup assign ioctl take the qgroup ioctl mutex
before calling btrfs_run_qgroups(), which is what all qgroup ioctls should
call.

Reported-by: butt3rflyh4ck <butterflyhuangxx@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CAFcO6XN3VD8ogmHwqRk4kbiwtpUSNySu2VAxN8waEPciCHJvMA@mail.gmail.com/
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>

Pull input fixes from Dmitry Torokhov:

- fixes to ALPS and Focaltech PS/2 drivers dealing with the breakage of
switching to -funsigned-char

- quirks to i8042 to better handle Lifebook A574/H and TUXEDO devices

- a quirk to Goodix touchscreen driver to handle Yoga Book X90F

- a fix for incorrectly merged patch to xpad game controller driver

* tag 'input-for-v6.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: i8042 - add TUXEDO devices to i8042 quirk tables for partial fix
Input: alps - fix compatibility with -funsigned-char
Input: focaltech - use explicitly signed char type
Input: xpad - fix incorrectly applied patch for MAP_PROFILE_BUTTON
Input: goodix - add Lenovo Yoga Book X90F to nine_bytes_report DMI table
Input: i8042 - add quirk for Fujitsu Lifebook A574/H

The SMB2_IOCTL check in the switch statement will never be true as we
return earlier from smb2_reconnect() if @smb2_command == SMB2_IOCTL.

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

powerpc sets up PF_KTHREAD and PF_IO_WORKER with a NULL pt_regs, which
from my (arguably very short) checking is not commonly done for other
archs. This is fine, except when PF_IO_WORKER's have been created and
the task does something that causes a coredump to be generated. Then we
get this crash:

Kernel attempted to read user page (160) - exploit attempt? (uid: 1000)
BUG: Kernel NULL pointer dereference on read at 0x00000160
Faulting instruction address: 0xc0000000000c3a60
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=32 NUMA pSeries
Modules linked in: bochs drm_vram_helper drm_kms_helper xts binfmt_misc ecb ctr syscopyarea sysfillrect cbc sysimgblt drm_ttm_helper aes_generic ttm sg libaes evdev joydev virtio_balloon vmx_crypto gf128mul drm dm_mod fuse loop configfs drm_panel_orientation_quirks ip_tables x_tables autofs4 hid_generic usbhid hid xhci_pci xhci_hcd usbcore usb_common sd_mod
CPU: 1 PID: 1982 Comm: ppc-crash Not tainted 6.3.0-rc2+ #88
Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries
NIP: c0000000000c3a60 LR: c000000000039944 CTR: c0000000000398e0
REGS: c0000000041833b0 TRAP: 0300 Not tainted (6.3.0-rc2+)
MSR: 800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 88082828 XER: 200400f8
...
NIP memcpy_power7+0x200/0x7d0
LR ppr_get+0x64/0xb0
Call Trace:
ppr_get+0x40/0xb0 (unreliable)
__regset_get+0x180/0x1f0
regset_get_alloc+0x64/0x90
elf_core_dump+0xb98/0x1b60
do_coredump+0x1c34/0x24a0
get_signal+0x71c/0x1410
do_notify_resume+0x140/0x6f0
interrupt_exit_user_prepare_main+0x29c/0x320
interrupt_exit_user_prepare+0x6c/0xa0
interrupt_return_srr_user+0x8/0x138

Because ppr_get() is trying to copy from a PF_IO_WORKER with a NULL
pt_regs.

Check for a valid pt_regs in both ppc_get/ppr_set, and return an error
if not set. The actual error value doesn't seem to be important here, so
just pick -EINVAL.

Fixes: fa439810cc1b ("powerpc/ptrace: Enable support for NT_PPPC_TAR, NT_PPC_PPR, NT_PPC_DSCR")
Cc: stable@vger.kernel.org # v4.8+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[mpe: Trim oops in change log, add Fixes & Cc stable]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/d9f63344-fe7c-56ae-b420-4a1a04a2ae4c@kernel.dk