In the Linux kernel, the following vulnerability has been resolved:
pstore/ram: Fix crash when setting number of cpus to an odd number
When the number of cpu cores is adjusted to 7 or other odd numbers,
the zone size will become an odd number.
The address of the zone will become:
addr of zone0 = BASE
addr of zone1 = BASE + zone_size
addr of zone2 = BASE + zone_size*2
...
The address of zone1/3/5/7 will be mapped to non-alignment va.
Eventually crashes will occur when accessing these va.
So, use ALIGN_DOWN() to make sure the zone size is even
to avoid this bug.
In the Linux kernel, the following vulnerability has been resolved:
x86/kvm: Disable kvmclock on all CPUs on shutdown
Currenly, we disable kvmclock from machine_shutdown() hook and this
only happens for boot CPU. We need to disable it for all CPUs to
guard against memory corruption e.g. on restore from hibernate.
Note, writing '0' to kvmclock MSR doesn't clear memory location, it
just prevents hypervisor from updating the location so for the short
while after write and while CPU is still alive, the clock remains usable
and correct so we don't need to switch to some other clocksource.
In the Linux kernel, the following vulnerability has been resolved:
x86/kvm: Teardown PV features on boot CPU as well
Various PV features (Async PF, PV EOI, steal time) work through memory
shared with hypervisor and when we restore from hibernation we must
properly teardown all these features to make sure hypervisor doesn't
write to stale locations after we jump to the previously hibernated kernel
(which can try to place anything there). For secondary CPUs the job is
already done by kvm_cpu_down_prepare(), register syscore ops to do
the same for boot CPU.
In the Linux kernel, the following vulnerability has been resolved:
btrfs: abort in rename_exchange if we fail to insert the second ref
Error injection stress uncovered a problem where we'd leave a dangling
inode ref if we failed during a rename_exchange. This happens because
we insert the inode ref for one side of the rename, and then for the
other side. If this second inode ref insert fails we'll leave the first
one dangling and leave a corrupt file system behind. Fix this by
aborting if we did the insert for the first inode ref.
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix data corruption by fallocate
When fallocate punches holes out of inode size, if original isize is in
the middle of last cluster, then the part from isize to the end of the
cluster will be zeroed with buffer write, at that time isize is not yet
updated to match the new size, if writeback is kicked in, it will invoke
ocfs2_writepage()->block_write_full_page() where the pages out of inode
size will be dropped. That will cause file corruption. Fix this by
zero out eof blocks when extending the inode size.
Running the following command with qemu-image 4.2.1 can get a corrupted
coverted image file easily.
qemu-img convert -p -t none -T none -f qcow2 $qcow_image \
-O qcow2 -o compat=1.1 $qcow_image.conv
The usage of fallocate in qemu is like this, it first punches holes out
of inode size, then extend the inode size.
fallocate(11, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 2276196352, 65536) = 0
fallocate(11, 0, 2276196352, 65536) = 0
v1: https://www.spinics.net/lists/linux-fsdevel/msg193999.html
v2: https://lore.kernel.org/linux-fsdevel/20210525093034.GB4112@quack2.suse.cz/T/
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix memory leak in ext4_mb_init_backend on error path.
Fix a memory leak discovered by syzbot when a file system is corrupted
with an illegally large s_log_groups_per_flex.
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix bug on in ext4_es_cache_extent as ext4_split_extent_at failed
We got follow bug_on when run fsstress with injecting IO fault:
[130747.323114] kernel BUG at fs/ext4/extents_status.c:762!
[130747.323117] Internal error: Oops - BUG: 0 [#1] SMP
......
[130747.334329] Call trace:
[130747.334553] ext4_es_cache_extent+0x150/0x168 [ext4]
[130747.334975] ext4_cache_extents+0x64/0xe8 [ext4]
[130747.335368] ext4_find_extent+0x300/0x330 [ext4]
[130747.335759] ext4_ext_map_blocks+0x74/0x1178 [ext4]
[130747.336179] ext4_map_blocks+0x2f4/0x5f0 [ext4]
[130747.336567] ext4_mpage_readpages+0x4a8/0x7a8 [ext4]
[130747.336995] ext4_readpage+0x54/0x100 [ext4]
[130747.337359] generic_file_buffered_read+0x410/0xae8
[130747.337767] generic_file_read_iter+0x114/0x190
[130747.338152] ext4_file_read_iter+0x5c/0x140 [ext4]
[130747.338556] __vfs_read+0x11c/0x188
[130747.338851] vfs_read+0x94/0x150
[130747.339110] ksys_read+0x74/0xf0
This patch's modification is according to Jan Kara's suggestion in:
https://patchwork.ozlabs.org/project/linux-ext4/patch/20210428085158.3728201-1-yebin10@huawei.com/
"I see. Now I understand your patch. Honestly, seeing how fragile is trying
to fix extent tree after split has failed in the middle, I would probably
go even further and make sure we fix the tree properly in case of ENOSPC
and EDQUOT (those are easily user triggerable). Anything else indicates a
HW problem or fs corruption so I'd rather leave the extent tree as is and
don't try to fix it (which also means we will not create overlapping
extents)."
In the Linux kernel, the following vulnerability has been resolved:
PM: sleep: Fix possible deadlocks in core system-wide PM code
It is reported that in low-memory situations the system-wide resume core
code deadlocks, because async_schedule_dev() executes its argument
function synchronously if it cannot allocate memory (and not only in
that case) and that function attempts to acquire a mutex that is already
held. Executing the argument function synchronously from within
dpm_async_fn() may also be problematic for ordering reasons (it may
cause a consumer device's resume callback to be invoked before a
requisite supplier device's one, for example).
Address this by changing the code in question to use
async_schedule_dev_nocall() for scheduling the asynchronous
execution of device suspend and resume functions and to directly
run them synchronously if async_schedule_dev_nocall() returns false.
In the Linux kernel, the following vulnerability has been resolved:
drm: Don't unref the same fb many times by mistake due to deadlock handling
If we get a deadlock after the fb lookup in drm_mode_page_flip_ioctl()
we proceed to unref the fb and then retry the whole thing from the top.
But we forget to reset the fb pointer back to NULL, and so if we then
get another error during the retry, before the fb lookup, we proceed
the unref the same fb again without having gotten another reference.
The end result is that the fb will (eventually) end up being freed
while it's still in use.
Reset fb to NULL once we've unreffed it to avoid doing it again
until we've done another fb lookup.
This turned out to be pretty easy to hit on a DG2 when doing async
flips (and CONFIG_DEBUG_WW_MUTEX_SLOWPATH=y). The first symptom I
saw that drm_closefb() simply got stuck in a busy loop while walking
the framebuffer list. Fortunately I was able to convince it to oops
instead, and from there it was easier to track down the culprit.
In the Linux kernel, the following vulnerability has been resolved:
UBSAN: array-index-out-of-bounds in dtSplitRoot
Syzkaller reported the following issue:
oop0: detected capacity change from 0 to 32768
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:1971:9
index -2 is out of range for type 'struct dtslot [128]'
CPU: 0 PID: 3613 Comm: syz-executor270 Not tainted 6.0.0-syzkaller-09423-g493ffd6605b2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
ubsan_epilogue lib/ubsan.c:151 [inline]
__ubsan_handle_out_of_bounds+0xdb/0x130 lib/ubsan.c:283
dtSplitRoot+0x8d8/0x1900 fs/jfs/jfs_dtree.c:1971
dtSplitUp fs/jfs/jfs_dtree.c:985 [inline]
dtInsert+0x1189/0x6b80 fs/jfs/jfs_dtree.c:863
jfs_mkdir+0x757/0xb00 fs/jfs/namei.c:270
vfs_mkdir+0x3b3/0x590 fs/namei.c:4013
do_mkdirat+0x279/0x550 fs/namei.c:4038
__do_sys_mkdirat fs/namei.c:4053 [inline]
__se_sys_mkdirat fs/namei.c:4051 [inline]
__x64_sys_mkdirat+0x85/0x90 fs/namei.c:4051
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fcdc0113fd9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffeb8bc67d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcdc0113fd9
RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003
RBP: 00007fcdc00d37a0 R08: 0000000000000000 R09: 00007fcdc00d37a0
R10: 00005555559a72c0 R11: 0000000000000246 R12: 00000000f8008000
R13: 0000000000000000 R14: 00083878000000f8 R15: 0000000000000000
</TASK>
The issue is caused when the value of fsi becomes less than -1.
The check to break the loop when fsi value becomes -1 is present
but syzbot was able to produce value less than -1 which cause the error.
This patch simply add the change for the values less than 0.
The patch is tested via syzbot.