In the Linux kernel, the following vulnerability has been resolved:
drm/hisilicon/hibmc: fix the hibmc loaded failed bug
When hibmc loaded failed, the driver use hibmc_unload to free the
resource, but the mutexes in mode.config are not init, which will
access an NULL pointer. Just change goto statement to return, because
hibnc_hw_init() doesn't need to free anything.
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: add null check
[WHY]
Prevents null pointer dereferences to enhance function robustness
[HOW]
Adds early null check and return false if invalid.
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 ]
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.
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
In the Linux kernel, the following vulnerability has been resolved:
mm/smaps: fix race between smaps_hugetlb_range and migration
smaps_hugetlb_range() handles the pte without holdling ptl, and may be
concurrenct with migration, leaing to BUG_ON in pfn_swap_entry_to_page().
The race is as follows.
smaps_hugetlb_range migrate_pages
huge_ptep_get
remove_migration_ptes
folio_unlock
pfn_swap_entry_folio
BUG_ON
To fix it, hold ptl lock in smaps_hugetlb_range().
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.
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/
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.
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]