Linux: >> Linux Kernel >> 3.14.46 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
net: bridge: fix soft lockup in br_multicast_query_expired()
When set multicast_query_interval to a large value, the local variable
'time' in br_multicast_send_query() may overflow. If the time is smaller
than jiffies, the timer will expire immediately, and then call mod_timer()
again, which creates a loop and may trigger the following soft lockup
issue.
watchdog: BUG: soft lockup - CPU#1 stuck for 221s! [rb_consumer:66]
CPU: 1 UID: 0 PID: 66 Comm: rb_consumer Not tainted 6.16.0+ #259 PREEMPT(none)
Call Trace:
<IRQ>
__netdev_alloc_skb+0x2e/0x3a0
br_ip6_multicast_alloc_query+0x212/0x1b70
__br_multicast_send_query+0x376/0xac0
br_multicast_send_query+0x299/0x510
br_multicast_query_expired.constprop.0+0x16d/0x1b0
call_timer_fn+0x3b/0x2a0
__run_timers+0x619/0x950
run_timer_softirq+0x11c/0x220
handle_softirqs+0x18e/0x560
__irq_exit_rcu+0x158/0x1a0
sysvec_apic_timer_interrupt+0x76/0x90
</IRQ>
This issue can be reproduced with:
ip link add br0 type bridge
echo 1 > /sys/class/net/br0/bridge/multicast_querier
echo 0xffffffffffffffff >
/sys/class/net/br0/bridge/multicast_query_interval
ip link set dev br0 up
The multicast_startup_query_interval can also cause this issue. Similar to
the commit 99b40610956a ("net: bridge: mcast: add and enforce query
interval minimum"), add check for the query interval maximum to fix this
issue.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-11
In the Linux kernel, the following vulnerability has been resolved:
ACPI: APEI: send SIGBUS to current task if synchronous memory error not recovered
If a synchronous error is detected as a result of user-space process
triggering a 2-bit uncorrected error, the CPU will take a synchronous
error exception such as Synchronous External Abort (SEA) on Arm64. The
kernel will queue a memory_failure() work which poisons the related
page, unmaps the page, and then sends a SIGBUS to the process, so that
a system wide panic can be avoided.
However, no memory_failure() work will be queued when abnormal
synchronous errors occur. These errors can include situations like
invalid PA, unexpected severity, no memory failure config support,
invalid GUID section, etc. In such a case, the user-space process will
trigger SEA again. This loop can potentially exceed the platform
firmware threshold or even trigger a kernel hard lockup, leading to a
system reboot.
Fix it by performing a force kill if no memory_failure() work is queued
for synchronous errors.
[ rjw: Changelog edits ]
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-11
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ctnetlink: remove refcounting in expectation dumpers
Same pattern as previous patch: do not keep the expectation object
alive via refcount, only store a cookie value and then use that
as the skip hint for dump resumption.
AFAICS this has the same issue as the one resolved in the conntrack
dumper, when we do
if (!refcount_inc_not_zero(&exp->use))
to increment the refcount, there is a chance that exp == last, which
causes a double-increment of the refcount and subsequent memory leak.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-11
In the Linux kernel, the following vulnerability has been resolved:
gfs2: Set .migrate_folio in gfs2_{rgrp,meta}_aops
Clears up the warning added in 7ee3647243e5 ("migrate: Remove call to
->writepage") that occurs in various xfstests, causing "something found
in dmesg" failures.
[ 341.136573] gfs2_meta_aops does not implement migrate_folio
[ 341.136953] WARNING: CPU: 1 PID: 36 at mm/migrate.c:944 move_to_new_folio+0x2f8/0x300
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-11
In the Linux kernel, the following vulnerability has been resolved:
fs: Prevent file descriptor table allocations exceeding INT_MAX
When sysctl_nr_open is set to a very high value (for example, 1073741816
as set by systemd), processes attempting to use file descriptors near
the limit can trigger massive memory allocation attempts that exceed
INT_MAX, resulting in a WARNING in mm/slub.c:
WARNING: CPU: 0 PID: 44 at mm/slub.c:5027 __kvmalloc_node_noprof+0x21a/0x288
This happens because kvmalloc_array() and kvmalloc() check if the
requested size exceeds INT_MAX and emit a warning when the allocation is
not flagged with __GFP_NOWARN.
Specifically, when nr_open is set to 1073741816 (0x3ffffff8) and a
process calls dup2(oldfd, 1073741880), the kernel attempts to allocate:
- File descriptor array: 1073741880 * 8 bytes = 8,589,935,040 bytes
- Multiple bitmaps: ~400MB
- Total allocation size: > 8GB (exceeding INT_MAX = 2,147,483,647)
Reproducer:
1. Set /proc/sys/fs/nr_open to 1073741816:
# echo 1073741816 > /proc/sys/fs/nr_open
2. Run a program that uses a high file descriptor:
#include <unistd.h>
#include <sys/resource.h>
int main() {
struct rlimit rlim = {1073741824, 1073741824};
setrlimit(RLIMIT_NOFILE, &rlim);
dup2(2, 1073741880); // Triggers the warning
return 0;
}
3. Observe WARNING in dmesg at mm/slub.c:5027
systemd commit a8b627a introduced automatic bumping of fs.nr_open to the
maximum possible value. The rationale was that systems with memory
control groups (memcg) no longer need separate file descriptor limits
since memory is properly accounted. However, this change overlooked
that:
1. The kernel's allocation functions still enforce INT_MAX as a maximum
size regardless of memcg accounting
2. Programs and tests that legitimately test file descriptor limits can
inadvertently trigger massive allocations
3. The resulting allocations (>8GB) are impractical and will always fail
systemd's algorithm starts with INT_MAX and keeps halving the value
until the kernel accepts it. On most systems, this results in nr_open
being set to 1073741816 (0x3ffffff8), which is just under 1GB of file
descriptors.
While processes rarely use file descriptors near this limit in normal
operation, certain selftests (like
tools/testing/selftests/core/unshare_test.c) and programs that test file
descriptor limits can trigger this issue.
Fix this by adding a check in alloc_fdtable() to ensure the requested
allocation size does not exceed INT_MAX. This causes the operation to
fail with -EMFILE instead of triggering a kernel warning and avoids the
impractical >8GB memory allocation request.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-11
In the Linux kernel, the following vulnerability has been resolved:
btrfs: qgroup: fix race between quota disable and quota rescan ioctl
There's a race between a task disabling quotas and another running the
rescan ioctl that can result in a use-after-free of qgroup records from
the fs_info->qgroup_tree rbtree.
This happens as follows:
1) Task A enters btrfs_ioctl_quota_rescan() -> btrfs_qgroup_rescan();
2) Task B enters btrfs_quota_disable() and calls
btrfs_qgroup_wait_for_completion(), which does nothing because at that
point fs_info->qgroup_rescan_running is false (it wasn't set yet by
task A);
3) Task B calls btrfs_free_qgroup_config() which starts freeing qgroups
from fs_info->qgroup_tree without taking the lock fs_info->qgroup_lock;
4) Task A enters qgroup_rescan_zero_tracking() which starts iterating
the fs_info->qgroup_tree tree while holding fs_info->qgroup_lock,
but task B is freeing qgroup records from that tree without holding
the lock, resulting in a use-after-free.
Fix this by taking fs_info->qgroup_lock at btrfs_free_qgroup_config().
Also at btrfs_qgroup_rescan() don't start the rescan worker if quotas
were already disabled.
CVSS Score
7.0
EPSS Score
0.0
Published
2025-09-11
In the Linux kernel, the following vulnerability has been resolved:
drm/msm: Add error handling for krealloc in metadata setup
Function msm_ioctl_gem_info_set_metadata() now checks for krealloc
failure and returns -ENOMEM, avoiding potential NULL pointer dereference.
Explicitly avoids __GFP_NOFAIL due to deadlock risks and allocation constraints.
Patchwork: https://patchwork.freedesktop.org/patch/661235/
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-11
In the Linux kernel, the following vulnerability has been resolved:
bpf: Forget ranges when refining tnum after JSET
Syzbot reported a kernel warning due to a range invariant violation on
the following BPF program.
0: call bpf_get_netns_cookie
1: if r0 == 0 goto <exit>
2: if r0 & Oxffffffff goto <exit>
The issue is on the path where we fall through both jumps.
That path is unreachable at runtime: after insn 1, we know r0 != 0, but
with the sign extension on the jset, we would only fallthrough insn 2
if r0 == 0. Unfortunately, is_branch_taken() isn't currently able to
figure this out, so the verifier walks all branches. The verifier then
refines the register bounds using the second condition and we end
up with inconsistent bounds on this unreachable path:
1: if r0 == 0 goto <exit>
r0: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0xffffffffffffffff)
2: if r0 & 0xffffffff goto <exit>
r0 before reg_bounds_sync: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0)
r0 after reg_bounds_sync: u64=[0x1, 0] var_off=(0, 0)
Improving the range refinement for JSET to cover all cases is tricky. We
also don't expect many users to rely on JSET given LLVM doesn't generate
those instructions. So instead of improving the range refinement for
JSETs, Eduard suggested we forget the ranges whenever we're narrowing
tnums after a JSET. This patch implements that approach.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-11
In the Linux kernel, the following vulnerability has been resolved:
jfs: truncate good inode pages when hard link is 0
The fileset value of the inode copy from the disk by the reproducer is
AGGR_RESERVED_I. When executing evict, its hard link number is 0, so its
inode pages are not truncated. This causes the bugon to be triggered when
executing clear_inode() because nrpages is greater than 0.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-11
In the Linux kernel, the following vulnerability has been resolved:
rcu: Fix rcu_read_unlock() deadloop due to IRQ work
During rcu_read_unlock_special(), if this happens during irq_exit(), we
can lockup if an IPI is issued. This is because the IPI itself triggers
the irq_exit() path causing a recursive lock up.
This is precisely what Xiongfeng found when invoking a BPF program on
the trace_tick_stop() tracepoint As shown in the trace below. Fix by
managing the irq_work state correctly.
irq_exit()
__irq_exit_rcu()
/* in_hardirq() returns false after this */
preempt_count_sub(HARDIRQ_OFFSET)
tick_irq_exit()
tick_nohz_irq_exit()
tick_nohz_stop_sched_tick()
trace_tick_stop() /* a bpf prog is hooked on this trace point */
__bpf_trace_tick_stop()
bpf_trace_run2()
rcu_read_unlock_special()
/* will send a IPI to itself */
irq_work_queue_on(&rdp->defer_qs_iw, rdp->cpu);
A simple reproducer can also be obtained by doing the following in
tick_irq_exit(). It will hang on boot without the patch:
static inline void tick_irq_exit(void)
{
+ rcu_read_lock();
+ WRITE_ONCE(current->rcu_read_unlock_special.b.need_qs, true);
+ rcu_read_unlock();
+
[neeraj: Apply Frederic's suggested fix for PREEMPT_RT]
CVSS Score
7.1
EPSS Score
0.0
Published
2025-09-11