In the Linux kernel, the following vulnerability has been resolved:
btrfs: harden block_group::bg_list against list_del() races
As far as I can tell, these calls of list_del_init() on bg_list cannot
run concurrently with btrfs_mark_bg_unused() or btrfs_mark_bg_to_reclaim(),
as they are in transaction error paths and situations where the block
group is readonly.
However, if there is any chance at all of racing with mark_bg_unused(),
or a different future user of bg_list, better to be safe than sorry.
Otherwise we risk the following interleaving (bg_list refcount in parens)
T1 (some random op) T2 (btrfs_mark_bg_unused)
!list_empty(&bg->bg_list); (1)
list_del_init(&bg->bg_list); (1)
list_move_tail (1)
btrfs_put_block_group (0)
btrfs_delete_unused_bgs
bg = list_first_entry
list_del_init(&bg->bg_list);
btrfs_put_block_group(bg); (-1)
Ultimately, this results in a broken ref count that hits zero one deref
early and the real final deref underflows the refcount, resulting in a WARNING.
In the Linux kernel, the following vulnerability has been resolved:
spi: fsl-qspi: use devm function instead of driver remove
Driver use devm APIs to manage clk/irq/resources and register the spi
controller, but the legacy remove function will be called first during
device detach and trigger kernel panic. Drop the remove function and use
devm_add_action_or_reset() for driver cleanup to ensure the release
sequence.
Trigger kernel panic on i.MX8MQ by
echo 30bb0000.spi >/sys/bus/platform/drivers/fsl-quadspi/unbind
In the Linux kernel, the following vulnerability has been resolved:
net/niu: Niu requires MSIX ENTRY_DATA fields touch before entry reads
Fix niu_try_msix() to not cause a fatal trap on sparc systems.
Set PCI_DEV_FLAGS_MSIX_TOUCH_ENTRY_DATA_FIRST on the struct pci_dev to
work around a bug in the hardware or firmware.
For each vector entry in the msix table, niu chips will cause a fatal
trap if any registers in that entry are read before that entries'
ENTRY_DATA register is written to. Testing indicates writes to other
registers are not sufficient to prevent the fatal trap, however the value
does not appear to matter. This only needs to happen once after power up,
so simply rebooting into a kernel lacking this fix will NOT cause the
trap.
NON-RESUMABLE ERROR: Reporting on cpu 64
NON-RESUMABLE ERROR: TPC [0x00000000005f6900] <msix_prepare_msi_desc+0x90/0xa0>
NON-RESUMABLE ERROR: RAW [4010000000000016:00000e37f93e32ff:0000000202000080:ffffffffffffffff
NON-RESUMABLE ERROR: 0000000800000000:0000000000000000:0000000000000000:0000000000000000]
NON-RESUMABLE ERROR: handle [0x4010000000000016] stick [0x00000e37f93e32ff]
NON-RESUMABLE ERROR: type [precise nonresumable]
NON-RESUMABLE ERROR: attrs [0x02000080] < ASI sp-faulted priv >
NON-RESUMABLE ERROR: raddr [0xffffffffffffffff]
NON-RESUMABLE ERROR: insn effective address [0x000000c50020000c]
NON-RESUMABLE ERROR: size [0x8]
NON-RESUMABLE ERROR: asi [0x00]
CPU: 64 UID: 0 PID: 745 Comm: kworker/64:1 Not tainted 6.11.5 #63
Workqueue: events work_for_cpu_fn
TSTATE: 0000000011001602 TPC: 00000000005f6900 TNPC: 00000000005f6904 Y: 00000000 Not tainted
TPC: <msix_prepare_msi_desc+0x90/0xa0>
g0: 00000000000002e9 g1: 000000000000000c g2: 000000c50020000c g3: 0000000000000100
g4: ffff8000470307c0 g5: ffff800fec5be000 g6: ffff800047a08000 g7: 0000000000000000
o0: ffff800014feb000 o1: ffff800047a0b620 o2: 0000000000000011 o3: ffff800047a0b620
o4: 0000000000000080 o5: 0000000000000011 sp: ffff800047a0ad51 ret_pc: 00000000005f7128
RPC: <__pci_enable_msix_range+0x3cc/0x460>
l0: 000000000000000d l1: 000000000000c01f l2: ffff800014feb0a8 l3: 0000000000000020
l4: 000000000000c000 l5: 0000000000000001 l6: 0000000020000000 l7: ffff800047a0b734
i0: ffff800014feb000 i1: ffff800047a0b730 i2: 0000000000000001 i3: 000000000000000d
i4: 0000000000000000 i5: 0000000000000000 i6: ffff800047a0ae81 i7: 00000000101888b0
I7: <niu_try_msix.constprop.0+0xc0/0x130 [niu]>
Call Trace:
[<00000000101888b0>] niu_try_msix.constprop.0+0xc0/0x130 [niu]
[<000000001018f840>] niu_get_invariants+0x183c/0x207c [niu]
[<00000000101902fc>] niu_pci_init_one+0x27c/0x2fc [niu]
[<00000000005ef3e4>] local_pci_probe+0x28/0x74
[<0000000000469240>] work_for_cpu_fn+0x8/0x1c
[<000000000046b008>] process_scheduled_works+0x144/0x210
[<000000000046b518>] worker_thread+0x13c/0x1c0
[<00000000004710e0>] kthread+0xb8/0xc8
[<00000000004060c8>] ret_from_fork+0x1c/0x2c
[<0000000000000000>] 0x0
Kernel panic - not syncing: Non-resumable error.
In the Linux kernel, the following vulnerability has been resolved:
mm/vmscan: don't try to reclaim hwpoison folio
Syzkaller reports a bug as follows:
Injecting memory failure for pfn 0x18b00e at process virtual address 0x20ffd000
Memory failure: 0x18b00e: dirty swapcache page still referenced by 2 users
Memory failure: 0x18b00e: recovery action for dirty swapcache page: Failed
page: refcount:2 mapcount:0 mapping:0000000000000000 index:0x20ffd pfn:0x18b00e
memcg:ffff0000dd6d9000
anon flags: 0x5ffffe00482011(locked|dirty|arch_1|swapbacked|hwpoison|node=0|zone=2|lastcpupid=0xfffff)
raw: 005ffffe00482011 dead000000000100 dead000000000122 ffff0000e232a7c9
raw: 0000000000020ffd 0000000000000000 00000002ffffffff ffff0000dd6d9000
page dumped because: VM_BUG_ON_FOLIO(!folio_test_uptodate(folio))
------------[ cut here ]------------
kernel BUG at mm/swap_state.c:184!
Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
Modules linked in:
CPU: 0 PID: 60 Comm: kswapd0 Not tainted 6.6.0-gcb097e7de84e #3
Hardware name: linux,dummy-virt (DT)
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : add_to_swap+0xbc/0x158
lr : add_to_swap+0xbc/0x158
sp : ffff800087f37340
x29: ffff800087f37340 x28: fffffc00052c0380 x27: ffff800087f37780
x26: ffff800087f37490 x25: ffff800087f37c78 x24: ffff800087f377a0
x23: ffff800087f37c50 x22: 0000000000000000 x21: fffffc00052c03b4
x20: 0000000000000000 x19: fffffc00052c0380 x18: 0000000000000000
x17: 296f696c6f662865 x16: 7461646f7470755f x15: 747365745f6f696c
x14: 6f6621284f494c4f x13: 0000000000000001 x12: ffff600036d8b97b
x11: 1fffe00036d8b97a x10: ffff600036d8b97a x9 : dfff800000000000
x8 : 00009fffc9274686 x7 : ffff0001b6c5cbd3 x6 : 0000000000000001
x5 : ffff0000c25896c0 x4 : 0000000000000000 x3 : 0000000000000000
x2 : 0000000000000000 x1 : ffff0000c25896c0 x0 : 0000000000000000
Call trace:
add_to_swap+0xbc/0x158
shrink_folio_list+0x12ac/0x2648
shrink_inactive_list+0x318/0x948
shrink_lruvec+0x450/0x720
shrink_node_memcgs+0x280/0x4a8
shrink_node+0x128/0x978
balance_pgdat+0x4f0/0xb20
kswapd+0x228/0x438
kthread+0x214/0x230
ret_from_fork+0x10/0x20
I can reproduce this issue with the following steps:
1) When a dirty swapcache page is isolated by reclaim process and the
page isn't locked, inject memory failure for the page.
me_swapcache_dirty() clears uptodate flag and tries to delete from lru,
but fails. Reclaim process will put the hwpoisoned page back to lru.
2) The process that maps the hwpoisoned page exits, the page is deleted
the page will never be freed and will be in the lru forever.
3) If we trigger a reclaim again and tries to reclaim the page,
add_to_swap() will trigger VM_BUG_ON_FOLIO due to the uptodate flag is
cleared.
To fix it, skip the hwpoisoned page in shrink_folio_list(). Besides, the
hwpoison folio may not be unmapped by hwpoison_user_mappings() yet, unmap
it in shrink_folio_list(), otherwise the folio will fail to be unmaped by
hwpoison_user_mappings() since the folio isn't in lru list.
In the Linux kernel, the following vulnerability has been resolved:
riscv: uprobes: Add missing fence.i after building the XOL buffer
The XOL (execute out-of-line) buffer is used to single-step the
replaced instruction(s) for uprobes. The RISC-V port was missing a
proper fence.i (i$ flushing) after constructing the XOL buffer, which
can result in incorrect execution of stale/broken instructions.
This was found running the BPF selftests "test_progs:
uprobe_autoattach, attach_probe" on the Spacemit K1/X60, where the
uprobes tests randomly blew up.
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix WARNING "do not call blocking ops when !TASK_RUNNING"
wait_event_timeout() will set the state of the current
task to TASK_UNINTERRUPTIBLE, before doing the condition check. This
means that ksmbd_durable_scavenger_alive() will try to acquire the mutex
while already in a sleeping state. The scheduler warns us by giving
the following warning:
do not call blocking ops when !TASK_RUNNING; state=2 set at
[<0000000061515a6f>] prepare_to_wait_event+0x9f/0x6c0
WARNING: CPU: 2 PID: 4147 at kernel/sched/core.c:10099 __might_sleep+0x12f/0x160
mutex lock is not needed in ksmbd_durable_scavenger_alive().
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix kmemleak warning for percpu hashmap
Vlad Poenaru reported the following kmemleak issue:
unreferenced object 0x606fd7c44ac8 (size 32):
backtrace (crc 0):
pcpu_alloc_noprof+0x730/0xeb0
bpf_map_alloc_percpu+0x69/0xc0
prealloc_init+0x9d/0x1b0
htab_map_alloc+0x363/0x510
map_create+0x215/0x3a0
__sys_bpf+0x16b/0x3e0
__x64_sys_bpf+0x18/0x20
do_syscall_64+0x7b/0x150
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Further investigation shows the reason is due to not 8-byte aligned
store of percpu pointer in htab_elem_set_ptr():
*(void __percpu **)(l->key + key_size) = pptr;
Note that the whole htab_elem alignment is 8 (for x86_64). If the key_size
is 4, that means pptr is stored in a location which is 4 byte aligned but
not 8 byte aligned. In mm/kmemleak.c, scan_block() scans the memory based
on 8 byte stride, so it won't detect above pptr, hence reporting the memory
leak.
In htab_map_alloc(), we already have
htab->elem_size = sizeof(struct htab_elem) +
round_up(htab->map.key_size, 8);
if (percpu)
htab->elem_size += sizeof(void *);
else
htab->elem_size += round_up(htab->map.value_size, 8);
So storing pptr with 8-byte alignment won't cause any problem and can fix
kmemleak too.
The issue can be reproduced with bpf selftest as well:
1. Enable CONFIG_DEBUG_KMEMLEAK config
2. Add a getchar() before skel destroy in test_hash_map() in prog_tests/for_each.c.
The purpose is to keep map available so kmemleak can be detected.
3. run './test_progs -t for_each/hash_map &' and a kmemleak should be reported.
In the Linux kernel, the following vulnerability has been resolved:
driver core: fix potential NULL pointer dereference in dev_uevent()
If userspace reads "uevent" device attribute at the same time as another
threads unbinds the device from its driver, change to dev->driver from a
valid pointer to NULL may result in crash. Fix this by using READ_ONCE()
when fetching the pointer, and take bus' drivers klist lock to make sure
driver instance will not disappear while we access it.
Use WRITE_ONCE() when setting the driver pointer to ensure there is no
tearing.
In the Linux kernel, the following vulnerability has been resolved:
bpf: consider that tail calls invalidate packet pointers
Tail-called programs could execute any of the helpers that invalidate
packet pointers. Hence, conservatively assume that each tail call
invalidates packet pointers.
Making the change in bpf_helper_changes_pkt_data() automatically makes
use of check_cfg() logic that computes 'changes_pkt_data' effect for
global sub-programs, such that the following program could be
rejected:
int tail_call(struct __sk_buff *sk)
{
bpf_tail_call_static(sk, &jmp_table, 0);
return 0;
}
SEC("tc")
int not_safe(struct __sk_buff *sk)
{
int *p = (void *)(long)sk->data;
... make p valid ...
tail_call(sk);
*p = 42; /* this is unsafe */
...
}
The tc_bpf2bpf.c:subprog_tc() needs change: mark it as a function that
can invalidate packet pointers. Otherwise, it can't be freplaced with
tailcall_freplace.c:entry_freplace() that does a tail call.