Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
drm/i915/gt: fix refcount underflow in intel_engine_park_heartbeat
A use-after-free / refcount underflow is possible when the heartbeat
worker and intel_engine_park_heartbeat() race to release the same
engine->heartbeat.systole request.
The heartbeat worker reads engine->heartbeat.systole and calls
i915_request_put() on it when the request is complete, but clears
the pointer in a separate, non-atomic step. Concurrently, a request
retirement on another CPU can drop the engine wakeref to zero, triggering
__engine_park() -> intel_engine_park_heartbeat(). If the heartbeat
timer is pending at that point, cancel_delayed_work() returns true and
intel_engine_park_heartbeat() reads the stale non-NULL systole pointer
and calls i915_request_put() on it again, causing a refcount underflow:
```
<4> [487.221889] Workqueue: i915-unordered engine_retire [i915]
<4> [487.222640] RIP: 0010:refcount_warn_saturate+0x68/0xb0
...
<4> [487.222707] Call Trace:
<4> [487.222711] <TASK>
<4> [487.222716] intel_engine_park_heartbeat.part.0+0x6f/0x80 [i915]
<4> [487.223115] intel_engine_park_heartbeat+0x25/0x40 [i915]
<4> [487.223566] __engine_park+0xb9/0x650 [i915]
<4> [487.223973] ____intel_wakeref_put_last+0x2e/0xb0 [i915]
<4> [487.224408] __intel_wakeref_put_last+0x72/0x90 [i915]
<4> [487.224797] intel_context_exit_engine+0x7c/0x80 [i915]
<4> [487.225238] intel_context_exit+0xf1/0x1b0 [i915]
<4> [487.225695] i915_request_retire.part.0+0x1b9/0x530 [i915]
<4> [487.226178] i915_request_retire+0x1c/0x40 [i915]
<4> [487.226625] engine_retire+0x122/0x180 [i915]
<4> [487.227037] process_one_work+0x239/0x760
<4> [487.227060] worker_thread+0x200/0x3f0
<4> [487.227068] ? __pfx_worker_thread+0x10/0x10
<4> [487.227075] kthread+0x10d/0x150
<4> [487.227083] ? __pfx_kthread+0x10/0x10
<4> [487.227092] ret_from_fork+0x3d4/0x480
<4> [487.227099] ? __pfx_kthread+0x10/0x10
<4> [487.227107] ret_from_fork_asm+0x1a/0x30
<4> [487.227141] </TASK>
```
Fix this by replacing the non-atomic pointer read + separate clear with
xchg() in both racing paths. xchg() is a single indivisible hardware
instruction that atomically reads the old pointer and writes NULL. This
guarantees only one of the two concurrent callers obtains the non-NULL
pointer and performs the put, the other gets NULL and skips it.
(cherry picked from commit 13238dc0ee4f9ab8dafa2cca7295736191ae2f42)
CVSS Score
7.8
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: hold claim backbone gateways by reference
batadv_bla_add_claim() can replace claim->backbone_gw and drop the old
gateway's last reference while readers still follow the pointer.
The netlink claim dump path dereferences claim->backbone_gw->orig and
takes claim->backbone_gw->crc_lock without pinning the underlying
backbone gateway. batadv_bla_check_claim() still has the same naked
pointer access pattern.
Reuse batadv_bla_claim_get_backbone_gw() in both readers so they operate
on a stable gateway reference until the read-side work is complete.
This keeps the dump and claim-check paths aligned with the lifetime
rules introduced for the other BLA claim readers.
CVSS Score
9.8
EPSS Score
0.001
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
net: altera-tse: fix skb leak on DMA mapping error in tse_start_xmit()
When dma_map_single() fails in tse_start_xmit(), the function returns
NETDEV_TX_OK without freeing the skb. Since NETDEV_TX_OK tells the
stack the packet was consumed, the skb is never freed, leaking memory
on every DMA mapping failure.
Add dev_kfree_skb_any() before returning to properly free the skb.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: reject oversized global TT response buffers
batadv_tt_prepare_tvlv_global_data() builds the allocation length for a
global TT response in 16-bit temporaries. When a remote originator
advertises a large enough global TT, the TT payload length plus the VLAN
header offset can exceed 65535 and wrap before kmalloc().
The full-table response path still uses the original TT payload length when
it fills tt_change, so the wrapped allocation is too small and
batadv_tt_prepare_tvlv_global_data() writes past the end of the heap object
before the later packet-size check runs.
Fix this by rejecting TT responses whose TVLV value length cannot fit in
the 16-bit TVLV payload length field.
CVSS Score
9.8
EPSS Score
0.001
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
nfc: pn533: allocate rx skb before consuming bytes
pn532_receive_buf() reports the number of accepted bytes to the serdev
core. The current code consumes bytes into recv_skb and may already hand
a complete frame to pn533_recv_frame() before allocating a fresh receive
buffer.
If that alloc_skb() fails, the callback returns 0 even though it has
already consumed bytes, and it leaves recv_skb as NULL for the next
receive callback. That breaks the receive_buf() accounting contract and
can also lead to a NULL dereference on the next skb_put_u8().
Allocate the receive skb lazily before consuming the next byte instead.
If allocation fails, return the number of bytes already accepted.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
wifi: brcmsmac: Fix dma_free_coherent() size
dma_alloc_consistent() may change the size to align it. The new size is
saved in alloced.
Change the free size to match the allocation size.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
tipc: fix bc_ackers underflow on duplicate GRP_ACK_MSG
The GRP_ACK_MSG handler in tipc_group_proto_rcv() currently decrements
bc_ackers on every inbound group ACK, even when the same member has
already acknowledged the current broadcast round.
Because bc_ackers is a u16, a duplicate ACK received after the last
legitimate ACK wraps the counter to 65535. Once wrapped,
tipc_group_bc_cong() keeps reporting congestion and later group
broadcasts on the affected socket stay blocked until the group is
recreated.
Fix this by ignoring duplicate or stale ACKs before touching bc_acked or
bc_ackers. This makes repeated GRP_ACK_MSG handling idempotent and
prevents the underflow path.
CVSS Score
7.5
EPSS Score
0.001
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
xfrm: hold dev ref until after transport_finish NF_HOOK
After async crypto completes, xfrm_input_resume() calls dev_put()
immediately on re-entry before the skb reaches transport_finish.
The skb->dev pointer is then used inside NF_HOOK and its okfn,
which can race with device teardown.
Remove the dev_put from the async resumption entry and instead
drop the reference after the NF_HOOK call in transport_finish,
using a saved device pointer since NF_HOOK may consume the skb.
This covers NF_DROP, NF_QUEUE and NF_STOLEN paths that skip
the okfn.
For non-transport exits (decaps, gro, drop) and secondary
async return points, release the reference inline when
async is set.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
idpf: fix PREEMPT_RT raw/bh spinlock nesting for async VC handling
Switch from using the completion's raw spinlock to a local lock in the
idpf_vc_xn struct. The conversion is safe because complete/_all() are
called outside the lock and there is no reason to share the completion
lock in the current logic. This avoids invalid wait context reported by
the kernel due to the async handler taking BH spinlock:
[ 805.726977] =============================
[ 805.726991] [ BUG: Invalid wait context ]
[ 805.727006] 7.0.0-rc2-net-devq-031026+ #28 Tainted: G S OE
[ 805.727026] -----------------------------
[ 805.727038] kworker/u261:0/572 is trying to lock:
[ 805.727051] ff190da6a8dbb6a0 (&vport_config->mac_filter_list_lock){+...}-{3:3}, at: idpf_mac_filter_async_handler+0xe9/0x260 [idpf]
[ 805.727099] other info that might help us debug this:
[ 805.727111] context-{5:5}
[ 805.727119] 3 locks held by kworker/u261:0/572:
[ 805.727132] #0: ff190da6db3e6148 ((wq_completion)idpf-0000:83:00.0-mbx){+.+.}-{0:0}, at: process_one_work+0x4b5/0x730
[ 805.727163] #1: ff3c6f0a6131fe50 ((work_completion)(&(&adapter->mbx_task)->work)){+.+.}-{0:0}, at: process_one_work+0x1e5/0x730
[ 805.727191] #2: ff190da765190020 (&x->wait#34){+.+.}-{2:2}, at: idpf_recv_mb_msg+0xc8/0x710 [idpf]
[ 805.727218] stack backtrace:
...
[ 805.727238] Workqueue: idpf-0000:83:00.0-mbx idpf_mbx_task [idpf]
[ 805.727247] Call Trace:
[ 805.727249] <TASK>
[ 805.727251] dump_stack_lvl+0x77/0xb0
[ 805.727259] __lock_acquire+0xb3b/0x2290
[ 805.727268] ? __irq_work_queue_local+0x59/0x130
[ 805.727275] lock_acquire+0xc6/0x2f0
[ 805.727277] ? idpf_mac_filter_async_handler+0xe9/0x260 [idpf]
[ 805.727284] ? _printk+0x5b/0x80
[ 805.727290] _raw_spin_lock_bh+0x38/0x50
[ 805.727298] ? idpf_mac_filter_async_handler+0xe9/0x260 [idpf]
[ 805.727303] idpf_mac_filter_async_handler+0xe9/0x260 [idpf]
[ 805.727310] idpf_recv_mb_msg+0x1c8/0x710 [idpf]
[ 805.727317] process_one_work+0x226/0x730
[ 805.727322] worker_thread+0x19e/0x340
[ 805.727325] ? __pfx_worker_thread+0x10/0x10
[ 805.727328] kthread+0xf4/0x130
[ 805.727333] ? __pfx_kthread+0x10/0x10
[ 805.727336] ret_from_fork+0x32c/0x410
[ 805.727345] ? __pfx_kthread+0x10/0x10
[ 805.727347] ret_from_fork_asm+0x1a/0x30
[ 805.727354] </TASK>
CVSS Score
5.5
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
mm: filemap: fix nr_pages calculation overflow in filemap_map_pages()
When running stress-ng on my Arm64 machine with v7.0-rc3 kernel, I
encountered some very strange crash issues showing up as "Bad page state":
"
[ 734.496287] BUG: Bad page state in process stress-ng-env pfn:415735fb
[ 734.496427] page: refcount:0 mapcount:1 mapping:0000000000000000 index:0x4cf316 pfn:0x415735fb
[ 734.496434] flags: 0x57fffe000000800(owner_2|node=1|zone=2|lastcpupid=0x3ffff)
[ 734.496439] raw: 057fffe000000800 0000000000000000 dead000000000122 0000000000000000
[ 734.496440] raw: 00000000004cf316 0000000000000000 0000000000000000 0000000000000000
[ 734.496442] page dumped because: nonzero mapcount
"
After analyzing this page’s state, it is hard to understand why the
mapcount is not 0 while the refcount is 0, since this page is not where
the issue first occurred. By enabling the CONFIG_DEBUG_VM config, I can
reproduce the crash as well and captured the first warning where the issue
appears:
"
[ 734.469226] page: refcount:33 mapcount:0 mapping:00000000bef2d187 index:0x81a0 pfn:0x415735c0
[ 734.469304] head: order:5 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
[ 734.469315] memcg:ffff000807a8ec00
[ 734.469320] aops:ext4_da_aops ino:100b6f dentry name(?):"stress-ng-mmaptorture-9397-0-2736200540"
[ 734.469335] flags: 0x57fffe400000069(locked|uptodate|lru|head|node=1|zone=2|lastcpupid=0x3ffff)
......
[ 734.469364] page dumped because: VM_WARN_ON_FOLIO((_Generic((page + nr_pages - 1),
const struct page *: (const struct folio *)_compound_head(page + nr_pages - 1), struct page *:
(struct folio *)_compound_head(page + nr_pages - 1))) != folio)
[ 734.469390] ------------[ cut here ]------------
[ 734.469393] WARNING: ./include/linux/rmap.h:351 at folio_add_file_rmap_ptes+0x3b8/0x468,
CPU#90: stress-ng-mlock/9430
[ 734.469551] folio_add_file_rmap_ptes+0x3b8/0x468 (P)
[ 734.469555] set_pte_range+0xd8/0x2f8
[ 734.469566] filemap_map_folio_range+0x190/0x400
[ 734.469579] filemap_map_pages+0x348/0x638
[ 734.469583] do_fault_around+0x140/0x198
......
[ 734.469640] el0t_64_sync+0x184/0x188
"
The code that triggers the warning is: "VM_WARN_ON_FOLIO(page_folio(page +
nr_pages - 1) != folio, folio)", which indicates that set_pte_range()
tried to map beyond the large folio’s size.
By adding more debug information, I found that 'nr_pages' had overflowed
in filemap_map_pages(), causing set_pte_range() to establish mappings for
a range exceeding the folio size, potentially corrupting fields of pages
that do not belong to this folio (e.g., page->_mapcount).
After above analysis, I think the possible race is as follows:
CPU 0 CPU 1
filemap_map_pages() ext4_setattr()
//get and lock folio with old inode->i_size
next_uptodate_folio()
.......
//shrink the inode->i_size
i_size_write(inode, attr->ia_size);
//calculate the end_pgoff with the new inode->i_size
file_end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE) - 1;
end_pgoff = min(end_pgoff, file_end);
......
//nr_pages can be overflowed, cause xas.xa_index > end_pgoff
end = folio_next_index(folio) - 1;
nr_pages = min(end, end_pgoff) - xas.xa_index + 1;
......
//map large folio
filemap_map_folio_range()
......
//truncate folios
truncate_pagecache(inode, inode->i_size);
To fix this issue, move the 'end_pgoff' calculation before
next_uptodate_folio(), so the retrieved folio stays consistent with the
file end to avoid
---truncated---
CVSS Score
7.8
EPSS Score
0.0
Published
2026-04-24