| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
net: Remove conflicting altnames for dying netns in __dev_change_net_namespace().
syzbot reported the warning in cfg80211_pernet_exit(). [0]
The repro does the following:
1. create two device in root netns and non-root netns
2. assign the same altname for the two devices
3. remove the non-root netns
Since commit 7663d522099e ("net: check for altname conflicts
when changing netdev's netns"), cfg80211_switch_netns() and
cfg802154_switch_netns() fail if init_net has a device with the
conflicting altname.
default_device_exit_net() had the same issue and commit d09486a04f5d
("net: fix removing a namespace with conflicting altnames") fixed it.
cfg80211_pernet_exit() and cfg802154_pernet_exit() need the same fix.
Let's generalise the fix by removing conflicting altnames for dying
netns in __dev_change_net_namespace().
[0]:
cfg80211_switch_netns(rdev, &init_net)
WARNING: net/wireless/core.c:1871 at cfg80211_pernet_exit+0xd5/0x120 net/wireless/core.c:1871, CPU#1: kworker/u8:9/1160
Modules linked in:
CPU: 1 UID: 0 PID: 1160 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: netns cleanup_net
RIP: 0010:cfg80211_pernet_exit+0xd5/0x120 net/wireless/core.c:1871
Code: e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 b4 ef 0e f7 4d 8b 36 49 81 fe 20 10 4a 90 74 12 e8 03 3d 9f f6 eb 85 e8 fc 3c 9f f6 90 <0f> 0b 90 eb cc e8 f1 3c 9f f6 eb 05 e8 ea 3c 9f f6 5b 41 5c 41 5e
RSP: 0018:ffffc900057a78f0 EFLAGS: 00010293
RAX: ffffffff8b287154 RBX: ffff88807ba72780 RCX: ffff8880213e8000
RDX: 0000000000000000 RSI: 00000000ffffffef RDI: 0000000000000000
RBP: 00000000ffffffef R08: ffffffff9024cc67 R09: 0000000000000000
R10: fffff52000af4eb0 R11: fffffbfff204998d R12: dffffc0000000000
R13: ffffffff904a1080 R14: ffff888144ed0008 R15: ffff888144ed0e20
FS: 0000000000000000(0000) GS:ffff888124de6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005642de0a8a70 CR3: 000000007a40c000 CR4: 00000000003526f0
Call Trace:
<TASK>
ops_exit_list net/core/net_namespace.c:200 [inline]
ops_undo_list+0x43d/0x8d0 net/core/net_namespace.c:253
cleanup_net+0x572/0x810 net/core/net_namespace.c:706
process_one_work kernel/workqueue.c:3387 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK> |
| In the Linux kernel, the following vulnerability has been resolved:
net: ethernet: oa_tc6: Improve the error recovery
When oversubscribed traffic causes lot of buffer overflow errors,
probably due to loss of data chunks, driver fails to find a
data chunk with end_valid bit set, before it runs out of sk buffer
space. As a result, assert is seen during skb_put.
Now, check is made if skb buffer has enough tailroom for the
incoming data before accepting. If there is no room, current
frame is abandoned and it will start looking for a data chunk
with start_valid bit, that is a new frame.
SK buffer allocation error is considered as recoverable error.
rx_buf_overflow flag is too specific and no longer the only
condition this flag is used for. Therefore it is renamed as
wait_until_start_valid. This is more appropriate as this flag
is used to look for the next data chunk with SV bit set, after
failures like buffer overflow, buffer allocation failure, skb pointer
validity besides buffer overflow error.
Not writing to status0 if it reads 0. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/pagemap: Prevent double migration of device pages
A device-private folio migrated to system memory by a CPU fault can
remain reachable through the raw-PFN eviction path until migration
finalization drops the source reference.
If eviction selects the same device-private folio during this window,
it can attempt to migrate the folio again. The second migration can leave
an uncharged folio on an LRU list, causing folio_lruvec_lock_irqsave() to
retry indefinitely and resulting in a soft lockup and RCU stall.
Mark successfully migrated device-private folios using a low bit of
their zone_device_data before migration finalization. Make both CPU-fault
and raw-PFN migration paths skip device-private folios carrying this
flag.
Mask the flag when retrieving the drm_pagemap_zdd pointer and preserve
it when a device-private folio is split. Keeping the state on the physical
folio also avoids depending on a virtual address that may change before a
fault occurs.
v2:
- Replace the retired-PFN XArray with an embedded bitmap. (Matthew Brost)
- Mark every base page covered by a migrated folio so retirement remains
valid if the folio is later split.
v3:
- Store the migrated state in a low bit of zone_device_data instead of
adding virtual-range and bitmap tracking to the ZDD. (Matthew Brost)
- Mask the flag when retrieving the ZDD and preserve it when splitting
a folio.
- Drop the pre-existing fixes already covered by Matthew Brost's series:
https://patchwork.freedesktop.org/series/171651/
v4:
- Advance by the folio size only for migration entries marked with
MIGRATE_PFN_COMPOUND. (Sashiko)
v5:
- Simplify ZDD flag updates and folio iteration. (Matthew Brost)
- Skip retired device-private folios in the CPU-fault path. (Matthew Brost)
- Preserve flag bits while taking a new ZDD reference for split folios.
v6:
- Restore MIGRATE_PFN_COMPOUND-aware stepping so non-compound migration
entries are processed one at a time. (Sashiko)
- Drop the pre-existing fixes already covered by Matthew Brost's series:
https://patchwork.freedesktop.org/series/171651/
The lockup was observed as:
[10109.860465] watchdog: BUG: soft lockup - CPU#9 stuck for 26s! [kworker/u65:5:6557]
[10109.860524] Tainted: [S]=CPU_OUT_OF_SPEC, [O]=OOT_MODULE
[10109.860524] Hardware name: ASUS System Product Name/PRIME Z790-P WIFI, BIOS 0812 02/24/2023
[10109.860525] Workqueue: xe_page_fault_work_queue xe_pagefault_queue_work [xe]
[10109.860644] RIP: 0010:_raw_spin_unlock_irqrestore+0x57/0x80
[10109.860655] Call Trace:
[10109.860655] <TASK>
[10109.860657] folio_lruvec_lock_irqsave+0x216/0x220
[10109.860661] ? __pfx_lru_add+0x10/0x10
[10109.860665] folio_batch_move_lru+0xc8/0x450
[10109.860670] ? lock_acquire+0xc4/0x2d0
[10109.860674] ? __folio_batch_add_and_move+0x60/0x2e0
[10109.860677] ? folio_migrate_mapping+0xa6/0x110
[10109.860679] ? folio_migrate_flags+0x13b/0x1b0
[10109.860681] ? __pfx_lru_add+0x10/0x10
[10109.860683] __folio_batch_add_and_move+0xe7/0x2e0
[10109.860685] ? dma_iova_try_alloc+0xb0/0x140
[10109.860689] folio_add_lru+0x64/0x80
[10109.860691] __migrate_device_finalize+0x12c/0x270
[10109.860695] migrate_device_finalize+0x10/0x20
[10109.860698] drm_pagemap_evict_to_ram+0x185/0x370 [drm_gpusvm_helper]
[10109.860704] ? drm_pagemap_evict_to_ram+0x96/0x370 [drm_gpusvm_helper]
[10109.860709] xe_svm_bo_evict+0x15/0x20 [xe]
[10109.860819] ? xe_svm_bo_evict+0x15/0x20 [xe]
[10109.860921] xe_bo_move+0x107e/0x1570 [xe]
[10109.860992] ? xe_ttm_tt_create+0x168/0x340 [xe]
[10109.861059] ? __up_read+0x98/0x2b0
[10109.861061] ? lock_is_held_type+0xa3/0x130
[10109.861067] ttm_bo_handle_move_mem+0xe8/0x1e0 [ttm]
[10109.861075] ttm_bo_evict+0x141/0x1c0 [ttm]
[10109.861081] ttm_bo_evict_cb+0x9f/0x100 [ttm]
[10109.861086] ttm_lru_walk_for_evict+0x84/0x190 [ttm]
[10109.861091] ? xe_ttm_vram_mgr_new+0x258/0x3a0 [xe]
[10109.861198] ttm_bo_alloc_resource+0x219/0
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: btintel: bound firmware ID by TLV length
The firmware ID is treated as a NUL-terminated string even though the
TLV length is its only boundary. If the value does not contain a NUL
terminator, snprintf() can read beyond the received response.
Limit the conversion to the advertised TLV value length. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Reject legacy packet loads from callbacks
check_ld_abs() models a failed BPF_LD_ABS or BPF_LD_IND in a
subprogram as an implicit return with R0 set to zero. It calls
prepare_func_exit() to explore this synthesized path.
When the load is reached directly from a synchronous callback,
prepare_func_exit() enforces the callback return contract and marks R0
precise. R0 is not derived from a real instruction on this path, so
precision backtracking reaches the callback call with R0 still requested
and triggers the "callback unexpected regs" verifier bug. A privileged
program loader can therefore cause a verifier warning and an -EFAULT
BPF_PROG_LOAD.
These legacy packet-load instructions are deprecated. Reject them from
callbacks rather than complicating their implicit-return model. Check all
active frames before constructing the implicit return so nested static
subprograms cannot hide the callback context.
Global functions are verified independently with a fresh frame zero, so
an active-frame check cannot identify a global function called from a
callback. Also check the complete subprogram call graph during stack-depth
validation and reject a function containing a legacy load when any caller
is a callback. This covers global and static descendants without making
has_ld_abs transitive, preserving its per-function BTF return-type check.
Ordinary uses outside callbacks remain supported. |
| In the Linux kernel, the following vulnerability has been resolved:
printk: Don't WARN on kthread_run failure.
Since __kthread_create_on_node() returns -EINTR upon SIGKILL,
we should not use WARN_ON() in order to catch kthread_run() failure. |
| In the Linux kernel, the following vulnerability has been resolved:
nvme: fix racy access to FDP placement id array
nvme_query_fdp_info() is called per-path and therefore prone to races.
It populates head->nr_plids/head->plids for fdp registration.
But nothing protects that pair from concurrent access - two paths scanning
the same namespace can race to populate it.
Avoid the race by moving this initialization work to nvme_alloc_ns_head()
which is called once per shared namespace. |
| In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix readahead synchronisation issues by loading all folios upfront
There are some synchronisation issues that derive from the app thread
adding more folios to the rolling buffer whilst the collector thread is
looking at them or trying to clear them, such as determining the setting of
front_folio_order when the next folio hasn't been added yet,
The reason for the rolling buffer approach is that loading the buffer
upfront and then dropping all the refs just acquired is quite a slow
operation, and loading progressively allows some of the cost to be deferred
until after at least some of the I/O is started.
Instead, a better way is to load all the folios into the rolling buffer
upfront - and then drop the refs later, once the I/O is in progress. (Even
better would be for the refs not to be there at all.)
Fix this by changing the rolling buffer loader to load all the folios
selected by the VM for readahead upfront into the folio queue. The folio
queue is allocated a batch worth at a time as we don't know how many folios
are involved (the readahead_control struct, alas, has a page count, not a
folio count).
The folio refs acquired from readahead are then dropped in bulk once the
first subrequest is dispatched as it's quite a slow operation. The
collector waits for NETFS_RREQ_NEED_PUT_RA_REFS to be cleared so that it
doesn't unlock folios before the xarray has been scanned for them.
This simplifies the buffer handling later and isn't noticeably slower as
the xarray doesn't need to be modified and the folios are all already
pre-locked. |
| In the Linux kernel, the following vulnerability has been resolved:
smb/client: invalidate fscache for fallocate range operations
smb3_zero_range(), smb3_punch_hole(), smb3_insert_range(), and
smb3_collapse_range() modify file contents through server-side range
operations. These operations discard the affected page cache, but leave
the FS-Cache cookie valid, so a later read may return data cached before
the range operation.
Fix this by invalidating FS-Cache after outstanding I/O has completed
and before modifying the file on the server.
Run the following as root on a CIFS mount with fsc enabled and an active
CacheFiles backend:
bash -c '
MNT=/mnt/cifs
FILE="$MNT/repro"
# Generate four 1 MiB random blocks: [A][B][C][D].
dd if=/dev/urandom of=/tmp/src bs=1M count=4 status=none
# Expected contents after zeroing B: [A][zero][C][D].
cp /tmp/src /tmp/expected
dd if=/dev/zero of=/tmp/expected bs=1M seek=1 count=1 \
conv=notrunc status=none
cp /tmp/src "$FILE"
# Populate FS-Cache, then discard the page cache.
sync
echo 1 > /proc/sys/vm/drop_caches
cat "$FILE" > /dev/null
sync
echo 1 > /proc/sys/vm/drop_caches
fallocate --zero-range -o 1M -l 1M "$FILE"
if cmp -s /tmp/expected "$FILE"; then
echo "readback: OK"
else
echo "readback: STALE DATA"
fi
'
Before this change, the readback differs from /tmp/expected:
readback: STALE DATA
After this change, it matches:
readback: OK |
| In the Linux kernel, the following vulnerability has been resolved:
smb/client: fix stale page cache in insert/collapse range
smb3_insert_range() and smb3_collapse_range() use
truncate_pagecache_range() to invalidate the affected page cache.
However, if off or old_eof is not page-aligned, the boundary pages are
only partially zeroed and remain uptodate. As a result, the client may
return stale data after a successful insert/collapse range operation.
For example, with 4K pages:
page 0 page 1 page 2
0------4K 4K------8K 8K------12K
^ ^
off=2K old_eof=10K
Page 1 is removed from the page cache, while the boundary pages are
only partially zeroed. After COPYCHUNK moves the data on the server,
these cached pages may still return stale data.
This can be reproduced on a CIFS mount:
bash -c '
FILE=/mnt/scratch/repro
# Use a 6 KiB file so EOF is not page-aligned.
dd if=/dev/urandom of=/tmp/src bs=1K count=6 status=none
# Expected: a 4 KiB hole followed by the original data.
rm -f /tmp/expected
truncate -s 4K /tmp/expected
cat /tmp/src >> /tmp/expected
cp /tmp/src "$FILE"
# Prime the page cache before moving data on the server.
cat "$FILE" > /dev/null
fallocate --insert-range -o 0 -l 4K "$FILE"
if cmp -s /tmp/expected "$FILE"; then
echo "readback: OK"
else
echo "readback: STALE DATA"
fi
'
Fix this by writing back dirty data and discarding the page cache from
the start of the page containing off to EOF before moving data on the
server. |
| In the Linux kernel, the following vulnerability has been resolved:
smb/client: validate new EOF for zero range
When FALLOC_FL_ZERO_RANGE is used without FALLOC_FL_KEEP_SIZE,
smb3_zero_range() may extend EOF without checking RLIMIT_FSIZE, allowing
the file to grow beyond the caller's file-size limit.
Fix this by calling inode_newsize_ok() before sending the zero-range
request when the operation would extend EOF.
Reproducer, using a file on a CIFS mount:
bash -c '
FILE=/mnt/cifs/repro
trap "" SIGXFSZ
ulimit -f 3072
truncate -s 2M "$FILE"
fallocate --zero-range -o 0 -l 4M "$FILE"
echo "fallocate rc=$?"
stat -c "file size=%s" "$FILE"
'
Before this change, the operation succeeds despite the 3 MiB limit:
fallocate rc=0
file size=4194304
After this change, fallocate fails and leaves the file at 2 MiB. |
| In the Linux kernel, the following vulnerability has been resolved:
smb/client: validate new EOF for insert range
smb3_insert_range() does not check if the new file size
(i_size + len) is valid. This allows FALLOC_FL_INSERT_RANGE to bypass
RLIMIT_FSIZE, exceed s_maxbytes, or produce a size outside the loff_t
range.
Use check_add_overflow() to calculate the new EOF. Validate it with
inode_newsize_ok() before modifying the file.
Reproducer, using a file on a CIFS mount:
bash -c '
FILE=/mnt/cifs/repro
trap "" SIGXFSZ
ulimit -f 3072 # RLIMIT_FSIZE = 3 MiB
# A regular write is stopped at 3 MiB.
dd if=/dev/zero of="$FILE" bs=1M count=4 status=none
stat -c "size after write: %s" "$FILE"
# Insert 2 MiB into a 2 MiB file.
truncate -s 2M "$FILE"
fallocate -i -o 0 -l 2M "$FILE"
stat -c "size after insert: %s" "$FILE"
'
Before this change, the regular write stops at the 3 MiB limit, but
insert range grows the file to 4 MiB:
dd: error writing '/mnt/cifs/repro': File too large
size after write: 3145728
size after insert: 4194304
After this change, insert range also fails at the limit and leaves the
2 MiB file unchanged:
dd: error writing '/mnt/cifs/repro': File too large
size after write: 3145728
fallocate: fallocate failed: File too large
size after insert: 2097152 |
| In the Linux kernel, the following vulnerability has been resolved:
erofs: disable LZ4 rolling decompression for now
LZ4 rolling decompression [1] was introduced to reduce the memory
footprint of temporary pages:
For many cases, it is needed for users to read small data within
a compressed extent (pcluster), either due to random small read, or
since uptodate folios (typically order-0) cannot be reused for
decompression again since decompression algorithm refills
already-uptodate folios.
Rolling decompression works because LZ4 is LZ77-based and only refers
to the most recent 64 KiB of decompressed data, so in theory only a
bounded rolling window of temporary pages is needed when decompressing.
It can save a lot of temporary memory, e.g.
601,960-byte data can be compressed into a 256k LZ4 compressed extent,
which means it needs 146 extra pages per request in the worst case if
rolling decompression is disabled.
However, the upstream LZ4 implementation is not under EROFS' control:
For example, the literal copy memmove() may still **copy long literals
backward** on x86 based on the address comparison even when the source
and destination ranges do not overlap (IOWs, inline decompression
doesn't need to be considered here). That breaks the rolling assumption
and makes the optimization broken.
Disable it for now to make sure the data correctness first since EROFS
is used everywhere now: The rolling window approach can be revived once
we either ensure that the official LZ4 code always copies forward for
non-overlapping ranges or maintain our own LZ4 implementation in EROFS.
The main impact is a higher runtime memory footprint; However, recent
commit 0f6273ab4637 ("erofs: add a reserved buffer pool for lz4
decompression") helps mitigate this when enabled but it's still not
perfect.
[1] https://www.usenix.org/conference/atc19/presentation/gao
ยง 3.3 Decompression |
| In the Linux kernel, the following vulnerability has been resolved:
net: reject oversized tx_queue_len at netlink parse time
rtnl_create_link() assigns IFLA_TXQLEN directly to dev->tx_queue_len
without going through netif_change_tx_queue_len(), so a device created
with "ip link add ... txqueuelen 500000" bypasses the S16_MAX cap and
still triggers the oversized ring allocations in pfifo_fast, tun and
tap. The veth peer nest (rtnl_nla_parse_ifinfomsg()) and the
RTM_NEWLINK-on-existing-device path reach the same sinks.
Enforce the cap in ifla_policy instead: IFLA_TXQLEN becomes
NLA_POLICY_FULL_RANGE(NLA_U32, &txqlen_range) with
txqlen_range = { .min = 0, .max = S16_MAX }. All netlink consumers
parse against this policy - rtnl_setlink(), rtnl_newlink() (create
and change), and the veth peer nest - so every netlink path is capped
at parse time and rejects the attribute with -ERANGE plus a proper
"integer out of range" extack message before any device state is
modified (the RTM_SETLINK half-application wart is gone with it).
Document the bound in the rt-link.yaml netlink spec.
Conditions to recreate the bug:
- CONFIG_NET_SCHED=y, CONFIG_VETH=y, CONFIG_USER_NS=y, CONFIG_NET_NS=y.
- Unprivileged user in a fresh user+net namespace (unshare -Urn):
ip link add v0 txqueuelen 500000 type veth peer name v1
-> on the fixed kernel this is rejected with -ERANGE ("integer out
of range" extack) instead of installing an oversized tx_queue_len
that later inflates pfifo_fast/tun/tap ring allocations.
- ip link set v0 txqueuelen 500000 is likewise rejected at parse time. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix subbuf resize races with trace_pipe_raw readers
Concurrent subbuffer resizes may crash trace_pipe_raw readers or leak
uninitialized memory to userspace due to stale size values.
Modify ring_buffer_alloc_read_page() to handle the resizing of an
existing buffer_data_read_page if necessary and add a new
ring_buffer_read_page_size(). This new function enables ring-buffer
buffer_data_read_page users to not call the racy
ring_buffer_subbuf_size_get(). This makes the spare_size member of
ftrace_buffer_info redundant.
Finally, handle buffer_data_read_page/reader_page order discrepancy in
ring_buffer_read_page(). On a mismatch simply copy manually the data to
the buffer_data_read_page. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Preserve inner map identity in callback frames
Callback frame constructors initialize map-typed argument registers with
__mark_reg_known_zero() and then restore map_ptr. This clears map_uid,
which is the only field distinguishing inner maps that share an
inner_map_meta template.
When a timer callback invokes bpf_for_each_map_elem() on a second inner
map, both the saved first map and the second map value can reach the nested
callback as the same template with map_uid zero. bpf_timer_init() then
accepts pairing the timer from the second map with the first map.
The runtime records the first map in the timer without taking a reference.
Freeing that map does not find the timer stored in the second map, so a
later timer callback dereferences the freed map.
Copy map_uid from the same caller register as map_ptr when constructing
for-each, timer/workqueue, and task-work callback arguments. The existing
identity check can then reject mismatched inner maps while allowing a
callback value to be paired with its actual map. |
| In the Linux kernel, the following vulnerability has been resolved:
xfs: don't spin forever on zero-length dirents when salvaging them
LOLLM noticed that xrep_dir_recover_data can spin forever if it
encounters an unused dirent that claims to have length zero. Fix that,
and prevent the same thing from happening with a zero-length entry. |
| In the Linux kernel, the following vulnerability has been resolved:
xfs: fix exchange-range reflink flag clearing issue with INO1_WRITTEN
When exchanging two full-file ranges, xmi_can_exchange_reflink_flags()
can move the reflink inode flag from the file that currently has it to
the other file, as long as exactly one side is marked. This assumes
that the file contents, and therefore all shared extents, are exchanged.
That assumption is not true when XFS_EXCHMAPS_INO1_WRITTEN is set.
xfs_exchmaps_can_skip_mapping() can skip hole and unwritten mappings
from file1, so an exchange can complete without moving every mapping
that the earlier flag-swap decision accounted for. In that case the
post-operation cleanup can clear the reflink flag from an inode that
still owns shared written extents. Later writes then take the
non-reflink write path and may update blocks that should still have
been protected by CoW, which shows up as data corruption between
reflink-related files.
Fix this by disabling the reflink flag exchange whenever
XFS_EXCHMAPS_INO1_WRITTEN is requested. The contents exchange can still
proceed; the conservative outcome is that both inodes keep the reflink
flag. The regular reflink flag cleanup path can drop the extra flag
later once the inode no longer has shared extents. |
| In the Linux kernel, the following vulnerability has been resolved:
xfs: fix the rtrmap and rtrefcount _maxlevels_ondisk functions
The _maxlevels_ondisk functions are used to compute the size of
in-memory btree cursors for each btree type. Unfortunately, LOLLM
noticed that the rtrmap and rtrefcount versions of these functions
forget to account for the inode root, which means that we could access
beyond the end of the cursor given a sufficiently large btree. Fix
this. |
| In the Linux kernel, the following vulnerability has been resolved:
afs: Clear stale peer app data after address list changes
afs_fs_probe_fileserver() fetches the current endpoint state under
server->fs_lock, but leaves old_alist as NULL. Consequently,
afs_set_peer_appdata() treats every address list replacement as initial
setup and only binds the new peers; it never unbinds peers removed from
the old list.
An address refresh can therefore proceed as follows. CPU 0 replaces
server S's list and drops Pold without clearing Pold->app_data. The
server destroyer then clears only S's current peers and lets S reach its
RCU callback. After the callback frees S, CPU 1 handles a callback
through an RxRPC connection that still pins Pold, reads Pold->app_data,
and calls afs_use_server() on the freed object.
KASAN reported:
BUG: KASAN: slab-use-after-free in afs_find_server+0x3c/0xa0
Read of size 4 at addr ffff8881013e1af0 by task krxrpcio/7001/74
Call Trace:
afs_find_server+0x3c/0xa0
afs_rx_new_call+0x15c/0x390
rxrpc_new_incoming_call+0x97c/0x1730
rxrpc_input_packet.constprop.0+0xd03/0xec0
rxrpc_io_thread+0x967/0x1640
Allocated by task 93:
afs_lookup_server+0x1a7/0x14c0
afs_alloc_server_list+0x43f/0xb60
afs_create_volume+0x923/0x1490
afs_get_tree+0x1c6/0x10a0
Freed by task 0:
kfree+0x131/0x3c0
rcu_core+0x50a/0x1850
Last potentially related work creation:
__call_rcu_common.constprop.0+0x71/0xa10
afs_put_server+0x213/0x2b0
Preserve old->addresses for the peer app-data update so that removed
peers are cleared before the endpoint state is replaced. Also advance
both cursors when the old and new lists share a peer; activating the
old/new comparison without this would otherwise loop forever on the
shared entry. |
