| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
ntfs: serialize resident iomap reads with mrec_lock
ntfs_read_iomap_begin_resident() walks the MFT record through
ntfs_attr_lookup() -> ntfs_attr_find() without taking ni->mrec_lock,
while ntfs_attr_record_resize(), ntfs_make_room_for_attr() and
ntfs_resident_attr_record_add() memmove() the same base_ni->mrec buffer
under that lock. map_mft_record() only takes a reference and does not
serialize, so the reader can observe torn attribute length and offset
fields while a writer is relocating the records.
KCSAN reports the race between the mmap read fault path and both link()
and unlink():
BUG: KCSAN: data-race in ntfs_attr_find / ntfs_attr_record_resize
write to 0xffff888100af1018 of 4 bytes by task 96 on cpu 1:
ntfs_attr_record_resize+0xd2/0x130
ntfs_attr_record_rm+0xad/0x530
ntfs_delete+0x224/0x640
ntfs_unlink+0x14d/0x280
vfs_unlink+0x157/0x520
read to 0xffff888100af1018 of 4 bytes by task 95 on cpu 0:
ntfs_attr_find+0x104/0x5b0
ntfs_attr_lookup+0x39c/0x10c0
ntfs_read_iomap_begin_resident+0xc6/0x230
ntfs_read_iomap_begin+0x5d/0xa0
iomap_iter+0x2e2/0x6e0
iomap_read_folio+0x147/0x2a0
ntfs_read_folio+0x108/0x170
filemap_read_folio+0x35/0x100
filemap_fault+0x993/0x1000
value changed: 0x00000250 -> 0x000001f0
The address is mrec + 0x18, i.e. mft_record.bytes_in_use, and the change
is the 96 bytes of one $FILE_NAME attribute being removed.
Keep base_ni->mrec_lock from the resident read iomap lookup through
iomap_end(). This protects both the attribute walk and the subsequent copy
from iomap->inline_data, which points into the MFT record. The non-resident
path is left alone: ntfs_lookup() already holds the directory inode's
mrec_lock when it reads an index folio through read_mapping_folio(), and
taking the lock in the shared wrapper deadlocks there with recursive locking
on mrec_lock. The comment above the read_mapping_folio() call in
fs/ntfs/dir.c notes the same hazard.
The seek path uses the same lookup helper but does not dereference
iomap->inline_data. Release the lock before returning from that path,
whereas the regular read path records base_ni in iomap->private and releases
the lock from its iomap_end() callback.
Tested with a reproducer that faults in a 16-byte resident file while
another thread runs link()/unlink() on it. Before: 40 KCSAN reports in
about one second. After: no reports in 180 seconds over 206,090 read
iterations and 423,540 link/unlink cycles. A PROVE_LOCKING build shows no
lockdep splat with the same reproducer running for 60 seconds. |
| In the Linux kernel, the following vulnerability has been resolved:
ntfs: reject unprivileged writes to reserved $LX* xattrs
Reject setxattr of the reserved $LXUID, $LXGID, $LXMOD and $LXDEV names
from userspace unless the caller has CAP_SYS_ADMIN. |
| In the Linux kernel, the following vulnerability has been resolved:
ntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()
ntfs_ir_to_ib copies all entries from index_root into a freshly allocated
index_block_size-byte buffer without verifying that the entries fit in the
available space. The entries in index_root may be larger than the usable
entry space in the index block.
This can cause OOB writes past the end of the allocation.
The validator ntfs_index_root_inconsistent() checks that entries are
self-consistent within the IR value, but never cross-checks them against
index_block_size. There is no bounds check in ntfs_ir_to_ib() before the
memcpy.
Fixing this at the sink in ntfs_ir_to_ib() since
ntfs_index_root_inconsistent() validates the logical consistency of
index_root as a structure and a root with large entries is a structurally
valid root. The bug is a size conflict of ntfs_ir_to_ib().
Also, the validator is called once per inode load in
ntfs_read_locked_inode() while ntfs_ir_to_ib() is only called during a
reparent, a check there adds no overhead to the common path.
Moreover, even a future call path that bypasses the validator would still
be protected.
With NULL as first parameter of ntfs_error(), the volume error flag is
never set by this call, so the device name will be absent from the error
message. In any case, that the caller, ntfs_ir_reparent(), prints an error
message that includes the device name on NULL returns.
I think this is the best solution available without adding
'struct super_block *sb' as a parameter to ntfs_ir_to_ib().
This heap out-of-bounds write is triggered by a crafted filesystem image,
which is not in the kernel threat model, anyway, fixing memory errors would
be nice to keep things secure. |
| In the Linux kernel, the following vulnerability has been resolved:
ipvs: fix integer overflow in ftp helper port/address parsing
ip_vs_ftp_get_addrport() accumulates decimal digits into a __u16
(hport) and into unsigned char (p[]) without checking for overflow.
A crafted FTP PASV/EPSV response with an over-long port or address
octet wraps the value, so the helper configures the data connection
with a truncated port/address.
The netfilter conntrack FTP helper had the same defect, fixed in
commit 2b413fc689ba ("netfilter: nf_conntrack_ftp: avoid u16
overflows"). Apply the equivalent fix here: widen the port accumulator
to u32 and reject values above 65535, and reject address octets above
255. |
| In the Linux kernel, the following vulnerability has been resolved:
NFSv4: remove callback IDR entry on client allocation failure
nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it
finishes setting up the client. If any later initialization step fails,
the error path frees the nfs_client directly with nfs_free_client(). That
bypasses nfs_put_client(), which is where the callback IDR entry is
removed during normal teardown.
A failed allocation can therefore leave cb_ident_idr pointing at a freed
nfs_client. A later NFSv4.0 callback lookup by cb_ident would find the
stale pointer and take a reference to it.
Make the callback IDR removal helper callable by the allocation failure
path, and remove the callback identifier before freeing the client.
This was found by a local static-analysis checker for publish-before-free
lifetime bugs and confirmed by manual inspection. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: fix RXDMAD_C buffer recycling race
The RXDMAD_C buffers come from the RRO data queues' page pools, which are
bound to a different NAPI, so the direct page-pool recycle used here could
race the owning NAPI; take the non-direct path as is already done for WED
RX queues. |
| In the Linux kernel, the following vulnerability has been resolved:
block: mtip32xx: synchronize ioctls with device removal
The ioctl handlers only test REMOVE_PENDING before entering
mtip_hw_ioctl(). Removal can set that bit immediately afterwards and free
dd->port in mtip_hw_exit() while an ioctl still dereferences it. An already
open block device can reach the handlers while del_gendisk() is in
progress.
Serialize both native and compat ioctls with removal. Set REMOVE_PENDING
before taking the mutex so new callers fail after an in-flight ioctl has
drained, and hold the mutex until the port has been torn down. |
| In the Linux kernel, the following vulnerability has been resolved:
null_blk: reject per-device queue resize for shared tag set
When shared_tags is enabled, null_setup_tagset() makes the device use the
global tag_set, whose driver_data stays NULL. null_map_queues() therefore
falls back to the module-wide g_submit_queues/g_poll_queues instead of any
per-device value.
Resizing submit_queues or poll_queues via configfs on such a device calls
blk_mq_update_nr_hw_queues() on the shared set, shrinking
set->nr_hw_queues. __blk_mq_realloc_hw_ctxs() only grows the
q->queue_hw_ctx[] allocation, so on shrink it merely exits and NULLs the
now-excess hctx slots. null_map_queues(), however, keeps mapping CPUs with
the unchanged g_submit_queues/g_poll_queues, so mq_map[] ends up pointing
at those NULLed hctx slots. blk_mq_map_swqueue() then dereferences the NULL
hctx (hctx->cpumask), crashing the kernel:
[ 460.218374] KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
[ 460.219003] CPU: 24 UID: 0 PID: 1492 Comm: sh Not tainted 7.2.0-rc2+ #67 PREEMPT(full)
[ 460.219792] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014
[ 460.220452] RIP: 0010:blk_mq_map_swqueue+0x4db/0x1430
......
[ 460.228977] Call Trace:
[ 460.229175] <TASK>
[ 460.229354] blk_mq_update_nr_hw_queues+0xd49/0x11c0
[ 460.229779] ? __pfx_blk_mq_update_nr_hw_queues+0x10/0x10
[ 460.230200] nullb_update_nr_hw_queues+0x1a9/0x370 [null_blk]
[ 460.230694] nullb_device_submit_queues_store+0xd9/0x170 [null_blk]
[ 460.231190] ? __pfx_nullb_device_submit_queues_store+0x10/0x10 [null_blk]
[ 460.231776] ? configfs_write_iter+0x35c/0x4e0
[ 460.232122] configfs_write_iter+0x286/0x4e0
[ 460.232460] vfs_write+0x52d/0xd00
[ 460.232779] ? __x64_sys_openat+0x108/0x1d0
[ 460.233106] ? __pfx_vfs_write+0x10/0x10
[ 460.233413] ? fdget_pos+0x1cf/0x4c0
[ 460.233745] ? fput_close+0x133/0x190
[ 460.234038] ? __pfx_expand_files+0x10/0x10
[ 460.234368] ksys_write+0xfc/0x1d0
Reproducer:
modprobe null_blk shared_tags=1 submit_queues=64 poll_queues=1
mkdir /sys/kernel/config/nullb/dev
echo 1 > /sys/kernel/config/nullb/dev/power
echo 1 > /sys/kernel/config/nullb/dev/submit_queues
A per-device resize of a shared tag set is meaningless anyway, so reject it
with -EINVAL in nullb_update_nr_hw_queues() when the device is bound to the
global tag_set. |
| In the Linux kernel, the following vulnerability has been resolved:
null_blk: free global tag_set on init error path
If shared_tags is enabled, null_setup_tagset() allocates the global tag_set
via null_init_global_tag_set(). If device creation later fails, err_dev
destroys the default devices and calls unregister_blkdev(), but never frees
the global tag_set. Since module init failed, null_exit() is never invoked,
so the global tag_set's tags and maps are permanently leaked.
Free the global tag_set in err_dev, matching null_exit() which does
if (tag_set.ops) blk_mq_free_tag_set(&tag_set). |
| In the Linux kernel, the following vulnerability has been resolved:
null_blk: register configfs subsystem after creating default devices
In null_init(), configfs_register_subsystem() currently runs before
register_blkdev(), so when null_blk is built as a module, a racing mkdir()
+ poweron from userspace can reach null_add_dev() while null_major is still
0. __add_disk() then hits WARN_ON(disk->minors) (major=0 with minors!=0)
and fails:
[root@fedora ~]# [ 2366.521436] WARNING: block/genhd.c:476 at __add_disk+0x8a7/0xde0,
[ 2366.523552] Modules linked in: null_blk(+) nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib
[ 2366.529081] CPU: 26 UID: 0 PID: 1600 Comm: sh Not tainted 7.2.0-rc1+ #66 PREEMPT(full)
......
[ 2366.547251] Call Trace:
[ 2366.547575] <TASK>
[ 2366.547831] ? _raw_spin_lock+0x84/0xe0
[ 2366.548260] add_disk_fwnode+0x114/0x560
[ 2366.548739] null_add_dev+0x102d/0x1b80 [null_blk]
[ 2366.549310] ? __pfx_null_add_dev+0x10/0x10 [null_blk]
[ 2366.549906] ? mutex_lock+0xde/0x1c0
[ 2366.550361] ? __pfx_mutex_lock+0x10/0x10
[ 2366.550827] nullb_device_power_store+0x1e7/0x280 [null_blk]
[ 2366.551499] ? __pfx_nullb_device_power_store+0x10/0x10 [null_blk]
[ 2366.552177] ? __kmalloc_cache_noprof+0x1f5/0x470
[ 2366.552748] ? configfs_write_iter+0x35c/0x4e0
[ 2366.553242] configfs_write_iter+0x286/0x4e0
[ 2366.553787] vfs_write+0x52d/0xd00
[ 2366.554169] ? __pfx_vfs_write+0x10/0x10
[ 2366.554679] ? __pfx___css_rstat_updated+0x10/0x10
[ 2366.555196] ? fdget_pos+0x1cf/0x4c0
[ 2366.555649] ksys_write+0xfc/0x1d0
......
Additionally, the err_dev path destroys all devices on nullb_list while
configfs is still registered. If a racing mkdir() + poweron puts a user
device on the list, null_destroy_dev()->null_free_dev() kfrees the user
device's nullb_device but /sys/kernel/config/nullb/<name> is still
reachable. Any userspace access to the item will trigger a UAF.
For simplicity, move configfs_register_subsystem() to the end to solve
the problems above. |
| In the Linux kernel, the following vulnerability has been resolved:
null_blk: use DEFINE_MUTEX for the file-scope mutex
In null_init(), mutex_init(&lock) currently happens after
configfs_register_subsystem(), which exposes the nullb subsystem to
userspace. A racing mkdir() into /sys/kernel/config/nullb/ can reach
null_find_dev_by_name() -> mutex_lock(&lock) before the mutex is
initialized, trigger warning:
[ 123.137788] DEBUG_LOCKS_WARN_ON(lock->magic != lock)
[ 123.137796] WARNING: kernel/locking/mutex.c:159 at mutex_lock+0x171/0x1c0, CPU#13: mkdir/1301
[ 123.140090] Modules linked in: null_blk(+) nft_fib_inet nft_fib_ipv4
......
[ 123.154926] Call Trace:
[ 123.155172] <TASK>
[ 123.155419] ? __pfx_mutex_lock+0x10/0x10
[ 123.156181] ? __pfx__raw_spin_lock+0x10/0x10
[ 123.156571] nullb_group_make_group+0x20/0x100 [null_blk]
[ 123.157011] configfs_mkdir+0x47b/0xc70
[ 123.157337] ? __pfx_configfs_mkdir+0x10/0x10
[ 123.157719] ? may_create_dentry+0x242/0x2e0
[ 123.158061] vfs_mkdir+0x2a9/0x6c0
[ 123.158352] filename_mkdirat+0x3dc/0x500
[ 123.158710] ? __pfx_filename_mkdirat+0x10/0x10
[ 123.159070] ? strncpy_from_user+0x3a/0x1d0
[ 123.159413] __x64_sys_mkdir+0x6b/0x90
[ 123.159760] do_syscall_64+0xea/0x600
Replace the runtime mutex_init(&lock) with a static DEFINE_MUTEX(lock)
declaration to fix this issue. |
| In the Linux kernel, the following vulnerability has been resolved:
mailbox: riscv-sbi-mpxy: validate RPMI notification lengths
The SBI return value controls how many bytes are copied from shared
memory into the RPMI notification buffer. It is not validated against
the negotiated shared-memory size before that copy. The event walker
also uses a reversed loop condition and can inspect a short event record.
Validate the complete notification length before copying it, iterate only
while a full event header remains, and stop when a declared event payload
extends beyond the copied notification data. |
| In the Linux kernel, the following vulnerability has been resolved:
coresight: etm4x: fix underflow for usage of (nrseqstate - 1)
According to IHI006H Embedded Trace Macrocell Architecture
Specification[0], TRCSEQEVR<n> is implemented only when
TRCIDR5.NUMSEQSTATE is 0b100, in which case n ranges from 0 to 2;
otherwise, TRCIDR5.NUMSEQSTATE is 0b000.
IOW, the number of usage in the initialisation or setting
TRCSEQEVR<n> with drvdata->nrseqstate - 1 in the loop could make
underflow issue when TRCIDR5.NUMSEQSTATE is 0b000.
Therefore, introduce nr_seq_ctrls field and untie it from nrseqstate.
As part of this introduce ETM_MAX_SEQ_TRANSITIONS macro and
apply nr_seq_ctrls and above macro to TRCSEQEVR<n> relevant fields setup. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Reject negative optlen in cgroup getsockopt hook
A cgroup getsockopt BPF program can shrink ctx->optlen after the
kernel getsockopt handler has run. The kernel-buffer variant, used by
TCP_ZEROCOPY_RECEIVE, only rejects values larger than the original
length.
If BPF writes a negative optlen, that value is accepted and propagated
back to the TCP getsockopt code. It can then be passed to
copy_to_sockptr() as a size_t and trigger the hardened usercopy
bytes > INT_MAX warning.
Reject negative ctx.optlen in __cgroup_bpf_run_filter_getsockopt_kern(),
matching the lower-bound validation already present in the sockptr-based
getsockopt hook. |
| In the Linux kernel, the following vulnerability has been resolved:
m68k: nfcon: Do not call console_is_registered() in nfcon_device()
Since 7c2af0f634f1 ("tty: tty_io: use console_list_lock for list
synchronization") show_cons_active() calls the .device() method under
the console_list_lock, but console_is_registered() tries to acquire
console_list_lock as well, causing a deadlock. It should not be
necessary to check console_is_registered() here since the function
should not be called in the fist place when the console is not
registered. |
| In the Linux kernel, the following vulnerability has been resolved:
lwt_bpf: Restore reserved headroom after xmit program
ip_finish_output2() expands an skb to LL_RESERVED_SPACE(dev) before LWT
xmit. An LWT_XMIT BPF program can then modify the skb head and still
return BPF_OK, so bpf_xmit() rechecks the remaining headroom before the
skb continues to neighbour output.
That recheck uses dst->dev->hard_header_len. This is not enough for the
neighbour cached-header path: neigh_hh_output() copies the cached hardware
header using the aligned hh_cache size, HH_DATA_MOD for short headers or
HH_DATA_ALIGN(hh_len) otherwise.
On Ethernet, hard_header_len is 14 but the cached copy needs 16 bytes. If
an LWT_XMIT BPF program calls bpf_skb_change_head(skb, 1, 0), the skb can
still have 15 bytes of headroom after the program. The existing check
accepts that, after which neigh_hh_output() hits its headroom warning and
drops the skb.
Use LL_RESERVED_SPACE(dst->dev) in the post-BPF headroom check to match
the reservation made before LWT xmit. |
| In the Linux kernel, the following vulnerability has been resolved:
smb/server: call ksmbd_proc_cleanup() on module init failure
When a later initializer fails, the unwind chain releases resources
created after procfs and then jumps directly to class_unregister().
Returning an error from module_init() leaves the proc tree and its
per-CPU counters allocated. |
| In the Linux kernel, the following vulnerability has been resolved:
smb/server: abort initialization when proc setup fails
ksmbd_server_init() calls ksmbd_proc_init() before creating the
remaining proc entries and server subsystems. ksmbd_proc_init() tears
down partial state on a procfs or percpu_counter allocation failure,
but returns void, so ksmbd_server_init() continues as if the counters
were usable.
Once userspace starts the server, server_ctrl_handle_init() calls
ksmbd_proc_reset(), which reaches percpu_counter_set() with a NULL
per-CPU counters pointer on SMP systems. The later ksmbd_proc_create()
calls also receive a NULL parent and may create entries in the /proc
root; ksmbd_proc_cleanup() cannot remove those entries because
ksmbd_proc_fs is NULL. |
| In the Linux kernel, the following vulnerability has been resolved:
smb: smbdirect: destroy QP before mem pools on accept failure
On the rdma_accept_failed error path of
smbdirect_accept_connect_request(), the receive io posted just above is
owned by the QP (recv_io is set to NULL after a successful post). The
error path fell through to smbdirect_connection_destroy_mem_pools()
before smbdirect_connection_destroy_qp(), so the mem pools and the
recv_io slab cache were destroyed while that recv_io was still
outstanding on the QP.
The drain in smbdirect_connection_destroy_qp() (ib_drain_qp()) is what
runs the recv completion that returns the recv_io to the free list, so
destroying the pools first leaves the object outstanding at
kmem_cache_destroy() time ("Slab cache still has objects") and later
frees it into an already-destroyed mempool (mempool_free_bulk
NULL-pointer dereference).
Give rdma_accept_failed its own teardown that drains the QP first, then
destroys the mem pools, and returns. The remaining labels
(post_recv_io_failed onward) run before the recv_io was ever posted, so
they keep the mem-pools-then-qp order.
The outstanding recv_io at kmem_cache_destroy() time:
[ 3487.344647] =============================================================================
[ 3487.349942] BUG smbdirect_recv_io_cache_ffff88811ba99000 (Not tainted): Objects remaining on __kmem_cache_shutdown()
[ 3487.356078] -----------------------------------------------------------------------------
[ 3487.356078]
[ 3487.356738] Object 0xffff8881511c3440 @offset=13376
[ 3487.358464] Allocated in mempool_alloc_noprof+0x18c/0x290 age=1194 cpu=6 pid=22254
[ 3487.361197] mempool_alloc_noprof+0x18c/0x290
[ 3487.361542] smbdirect_connection_create_mem_pools+0x405/0x780
[ 3487.361972] smbdirect_accept_connect_request+0x5a8/0x1b80
[ 3487.362359] smbdirect_listen_rdma_event_handler+0x1579/0x1b90
[ 3487.362779] cma_cm_event_handler+0x9c/0x230
[ 3487.363096] cma_ib_req_handler+0x2682/0x45d0
[ 3487.363414] cm_process_work+0x56/0x3d0
[ 3487.363676] cm_work_handler+0x8a0e/0xd000
[ 3487.367496] process_scheduled_works+0xa07/0x13a0
[ 3487.367859] worker_thread+0x7c9/0xc80
[ 3487.368148] kthread+0x341/0x430
[ 3487.368407] ret_from_fork+0x3a8/0x7a0
[ 3487.368704] ret_from_fork_asm+0x1a/0x30
[ 3487.370307] Slab 0xffffea0005447000 objects=19 used=1 fp=0xffff8881511c0040 flags=0x100000000000240(workingset|head|node=0|zone=2)
[ 3487.372840] ------------[ cut here ]------------
[ 3487.373195] WARNING: mm/slub.c:1244 at __slab_err+0x1a/0x30, CPU#6: kworker/6:84/22254
[ 3487.373759] Modules linked in:
[ 3487.373993] CPU: 6 UID: 0 PID: 22254 Comm: kworker/6:84 Tainted: G B 7.1.0-next-20260623+ #88 PREEMPT(lazy)
[ 3487.374778] Tainted: [B]=BAD_PAGE
[ 3487.377830] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
[ 3487.378515] Workqueue: ib_cm cm_work_handler
[ 3487.378820] RIP: 0010:__slab_err+0x1a/0x30
[ 3487.379129] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 e8 36 00 00 00 bf 05 00 00 00 be 01 00 00 00 e8 f7 75 45 00 90 <0f> 0b 90 c3 cc cc cc cc cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00
[ 3487.383255] RSP: 0018:ffff888220fc7050 EFLAGS: 00010093
[ 3487.383643] RAX: ffffffff8168e60a RBX: ffff88810955e640 RCX: ffff88821c381d80
[ 3487.384158] RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff870fa080
[ 3487.384662] RBP: ffff888220fc7068 R08: ffffffff870fa087 R09: 1ffffffff0e1f410
[ 3487.385192] R10: dffffc0000000000 R11: fffffbfff0e1f411 R12: ffffea0005447210
[ 3487.385674] R13: ffffea0005447000 R14: ffff888220fc7068 R15: ffff88812a8ab300
[ 3487.388932] FS: 0000000000000000(0000) GS:ffff888427e76000(0000) knlGS:0000000000000000
[ 3487.389529] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3487.389934] CR2: 00007ffcf2d84fd8 CR3: 0000000111d64006 CR4: 0000000000f72ef0
[ 3487.390440] PKRU: 55555554
[ 3487.390641] Call Trace:
[ 3487.390826] <TASK>
[ 3
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
null_blk: serialize configfs attribute updates with device setup
The attribute store methods generated with NULLB_DEVICE_ATTR() refuse to
change the configuration of a live device by testing
NULLB_DEV_FL_CONFIGURED, but that flag is only set by
nullb_device_power_store() after null_add_dev() has returned, and the
store methods take no lock at all. configfs only serializes writes to
the same open file (buffer->mutex), so a write to any attribute can run
concurrently with null_add_dev() and change the device configuration
while it is being used.
null_add_dev() reads the configuration several times, e.g. dev->zoned is
read once to set up the queue limits and once to initialize the zone
resources:
CPU0: echo 1 > nullb0/power CPU1: echo 1 > nullb0/zoned
nullb_device_power_store()
mutex_lock(&lock)
null_add_dev()
if (dev->zoned) -> false
/* no BLK_FEAT_ZONED */ nullb_device_zoned_store()
test_bit(FL_CONFIGURED) -> 0
dev->zoned = true
blk_mq_alloc_disk()
/* queue is not zoned */
if (nullb->dev->zoned) -> true
null_register_zoned_dev()
blk_revalidate_disk_zones()
blk_revalidate_disk_zones() is then called for a queue that does not
have BLK_FEAT_ZONED set, which triggers its WARN_ON_ONCE() and fails the
device setup with -EIO:
WARNING: CPU: 2 PID: 322 at block/blk-zoned.c:2357 blk_revalidate_disk_zones+0x4c/0x560
Clearing dev->zoned in the same window is worse: the queue is created
with BLK_FEAT_ZONED but the zone resources are never initialized, so
add_disk() succeeds for a zoned disk that has no zones. And a store that
lands after the last dev->zoned test leaves dev->zoned set while
dev->zones is still NULL, which null_process_zoned_cmd() dereferences on
the first write.
Fix this by taking the global lock, which nullb_device_power_store()
already holds across null_add_dev() and null_del_dev(), around both the
NULLB_DEV_FL_CONFIGURED test and the update of the device configuration.
The submit_queues and poll_queues apply callbacks are now called with
that lock held, so remove the locking they did themselves.
Since the store methods can run as soon as configfs_register_subsystem()
returns, that is, before null_init() gets to mutex_init(&lock), also
initialize the lock statically with DEFINE_MUTEX(). |
