| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: fix ext4_mb_mark_bb() with flex_bg with fast_commit
In case of flex_bg feature (which is by default enabled), extents for
any given inode might span across blocks from two different block group.
ext4_mb_mark_bb() only reads the buffer_head of block bitmap once for the
starting block group, but it fails to read it again when the extent length
boundary overflows to another block group. Then in this below loop it
accesses memory beyond the block group bitmap buffer_head and results
into a data abort.
for (i = 0; i < clen; i++)
if (!mb_test_bit(blkoff + i, bitmap_bh->b_data) == !state)
already++;
This patch adds this functionality for checking block group boundary in
ext4_mb_mark_bb() and update the buffer_head(bitmap_bh) for every different
block group.
w/o this patch, I was easily able to hit a data access abort using Power platform.
<...>
[ 74.327662] EXT4-fs error (device loop3): ext4_mb_generate_buddy:1141: group 11, block bitmap and bg descriptor inconsistent: 21248 vs 23294 free clusters
[ 74.533214] EXT4-fs (loop3): shut down requested (2)
[ 74.536705] Aborting journal on device loop3-8.
[ 74.702705] BUG: Unable to handle kernel data access on read at 0xc00000005e980000
[ 74.703727] Faulting instruction address: 0xc0000000007bffb8
cpu 0xd: Vector: 300 (Data Access) at [c000000015db7060]
pc: c0000000007bffb8: ext4_mb_mark_bb+0x198/0x5a0
lr: c0000000007bfeec: ext4_mb_mark_bb+0xcc/0x5a0
sp: c000000015db7300
msr: 800000000280b033
dar: c00000005e980000
dsisr: 40000000
current = 0xc000000027af6880
paca = 0xc00000003ffd5200 irqmask: 0x03 irq_happened: 0x01
pid = 5167, comm = mount
<...>
enter ? for help
[c000000015db7380] c000000000782708 ext4_ext_clear_bb+0x378/0x410
[c000000015db7400] c000000000813f14 ext4_fc_replay+0x1794/0x2000
[c000000015db7580] c000000000833f7c do_one_pass+0xe9c/0x12a0
[c000000015db7710] c000000000834504 jbd2_journal_recover+0x184/0x2d0
[c000000015db77c0] c000000000841398 jbd2_journal_load+0x188/0x4a0
[c000000015db7880] c000000000804de8 ext4_fill_super+0x2638/0x3e10
[c000000015db7a40] c0000000005f8404 get_tree_bdev+0x2b4/0x350
[c000000015db7ae0] c0000000007ef058 ext4_get_tree+0x28/0x40
[c000000015db7b00] c0000000005f6344 vfs_get_tree+0x44/0x100
[c000000015db7b70] c00000000063c408 path_mount+0xdd8/0xe70
[c000000015db7c40] c00000000063c8f0 sys_mount+0x450/0x550
[c000000015db7d50] c000000000035770 system_call_exception+0x4a0/0x4e0
[c000000015db7e10] c00000000000c74c system_call_common+0xec/0x250 |
| In the Linux kernel, the following vulnerability has been resolved:
parisc: Fix non-access data TLB cache flush faults
When a page is not present, we get non-access data TLB faults from
the fdc and fic instructions in flush_user_dcache_range_asm and
flush_user_icache_range_asm. When these occur, the cache line is
not invalidated and potentially we get memory corruption. The
problem was hidden by the nullification of the flush instructions.
These faults also affect performance. With pa8800/pa8900 processors,
there will be 32 faults per 4 KB page since the cache line is 128
bytes. There will be more faults with earlier processors.
The problem is fixed by using flush_cache_pages(). It does the flush
using a tmp alias mapping.
The flush_cache_pages() call in flush_cache_range() flushed too
large a range.
V2: Remove unnecessary preempt_disable() and preempt_enable() calls. |
| In the Linux kernel, the following vulnerability has been resolved:
ntfs: add sanity check on allocation size
ntfs_read_inode_mount invokes ntfs_malloc_nofs with zero allocation
size. It triggers one BUG in the __ntfs_malloc function.
Fix this by adding sanity check on ni->attr_list_size. |
| In the Linux kernel, the following vulnerability has been resolved:
video: fbdev: sm712fb: Fix crash in smtcfb_write()
When the sm712fb driver writes three bytes to the framebuffer, the
driver will crash:
BUG: unable to handle page fault for address: ffffc90001ffffff
RIP: 0010:smtcfb_write+0x454/0x5b0
Call Trace:
vfs_write+0x291/0xd60
? do_sys_openat2+0x27d/0x350
? __fget_light+0x54/0x340
ksys_write+0xce/0x190
do_syscall_64+0x43/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
Fix it by removing the open-coded endianness fixup-code. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Fix premature hw access after PCI error
After a recoverable PCI error has been detected and recovered, qla driver
needs to check to see if the error condition still persist and/or wait
for the OS to give the resume signal.
Sep 8 22:26:03 localhost kernel: WARNING: CPU: 9 PID: 124606 at qla_tmpl.c:440
qla27xx_fwdt_entry_t266+0x55/0x60 [qla2xxx]
Sep 8 22:26:03 localhost kernel: RIP: 0010:qla27xx_fwdt_entry_t266+0x55/0x60
[qla2xxx]
Sep 8 22:26:03 localhost kernel: Call Trace:
Sep 8 22:26:03 localhost kernel: ? qla27xx_walk_template+0xb1/0x1b0 [qla2xxx]
Sep 8 22:26:03 localhost kernel: ? qla27xx_execute_fwdt_template+0x12a/0x160
[qla2xxx]
Sep 8 22:26:03 localhost kernel: ? qla27xx_fwdump+0xa0/0x1c0 [qla2xxx]
Sep 8 22:26:03 localhost kernel: ? qla2xxx_pci_mmio_enabled+0xfb/0x120
[qla2xxx]
Sep 8 22:26:03 localhost kernel: ? report_mmio_enabled+0x44/0x80
Sep 8 22:26:03 localhost kernel: ? report_slot_reset+0x80/0x80
Sep 8 22:26:03 localhost kernel: ? pci_walk_bus+0x70/0x90
Sep 8 22:26:03 localhost kernel: ? aer_dev_correctable_show+0xc0/0xc0
Sep 8 22:26:03 localhost kernel: ? pcie_do_recovery+0x1bb/0x240
Sep 8 22:26:03 localhost kernel: ? aer_recover_work_func+0xaa/0xd0
Sep 8 22:26:03 localhost kernel: ? process_one_work+0x1a7/0x360
..
Sep 8 22:26:03 localhost kernel: qla2xxx [0000:42:00.2]-8041:22: detected PCI
disconnect.
Sep 8 22:26:03 localhost kernel: qla2xxx [0000:42:00.2]-107ff:22:
qla27xx_fwdt_entry_t262: dump ram MB failed. Area 5h start 198013h end 198013h
Sep 8 22:26:03 localhost kernel: qla2xxx [0000:42:00.2]-107ff:22: Unable to
capture FW dump
Sep 8 22:26:03 localhost kernel: qla2xxx [0000:42:00.2]-1015:22: cmd=0x0,
waited 5221 msecs
Sep 8 22:26:03 localhost kernel: qla2xxx [0000:42:00.2]-680d:22: mmio
enabled returning.
Sep 8 22:26:03 localhost kernel: qla2xxx [0000:42:00.2]-d04c:22: MBX
Command timeout for cmd 0, iocontrol=ffffffff jiffies=10140f2e5
mb[0-3]=[0xffff 0xffff 0xffff 0xffff] |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Fix scheduling while atomic
The driver makes a call into midlayer (fc_remote_port_delete) which can put
the thread to sleep. The thread that originates the call is in interrupt
context. The combination of the two trigger a crash. Schedule the call in
non-interrupt context where it is more safe.
kernel: BUG: scheduling while atomic: swapper/7/0/0x00010000
kernel: Call Trace:
kernel: <IRQ>
kernel: dump_stack+0x66/0x81
kernel: __schedule_bug.cold.90+0x5/0x1d
kernel: __schedule+0x7af/0x960
kernel: schedule+0x28/0x80
kernel: schedule_timeout+0x26d/0x3b0
kernel: wait_for_completion+0xb4/0x140
kernel: ? wake_up_q+0x70/0x70
kernel: __wait_rcu_gp+0x12c/0x160
kernel: ? sdev_evt_alloc+0xc0/0x180 [scsi_mod]
kernel: synchronize_sched+0x6c/0x80
kernel: ? call_rcu_bh+0x20/0x20
kernel: ? __bpf_trace_rcu_invoke_callback+0x10/0x10
kernel: sdev_evt_alloc+0xfd/0x180 [scsi_mod]
kernel: starget_for_each_device+0x85/0xb0 [scsi_mod]
kernel: ? scsi_init_io+0x360/0x3d0 [scsi_mod]
kernel: scsi_init_io+0x388/0x3d0 [scsi_mod]
kernel: device_for_each_child+0x54/0x90
kernel: fc_remote_port_delete+0x70/0xe0 [scsi_transport_fc]
kernel: qla2x00_schedule_rport_del+0x62/0xf0 [qla2xxx]
kernel: qla2x00_mark_device_lost+0x9c/0xd0 [qla2xxx]
kernel: qla24xx_handle_plogi_done_event+0x55f/0x570 [qla2xxx]
kernel: qla2x00_async_login_sp_done+0xd2/0x100 [qla2xxx]
kernel: qla24xx_logio_entry+0x13a/0x3c0 [qla2xxx]
kernel: qla24xx_process_response_queue+0x306/0x400 [qla2xxx]
kernel: qla24xx_msix_rsp_q+0x3f/0xb0 [qla2xxx]
kernel: __handle_irq_event_percpu+0x40/0x180
kernel: handle_irq_event_percpu+0x30/0x80
kernel: handle_irq_event+0x36/0x60 |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Suppress a kernel complaint in qla_create_qpair()
[ 12.323788] BUG: using smp_processor_id() in preemptible [00000000] code: systemd-udevd/1020
[ 12.332297] caller is qla2xxx_create_qpair+0x32a/0x5d0 [qla2xxx]
[ 12.338417] CPU: 7 PID: 1020 Comm: systemd-udevd Tainted: G I --------- --- 5.14.0-29.el9.x86_64 #1
[ 12.348827] Hardware name: Dell Inc. PowerEdge R610/0F0XJ6, BIOS 6.6.0 05/22/2018
[ 12.356356] Call Trace:
[ 12.358821] dump_stack_lvl+0x34/0x44
[ 12.362514] check_preemption_disabled+0xd9/0xe0
[ 12.367164] qla2xxx_create_qpair+0x32a/0x5d0 [qla2xxx]
[ 12.372481] qla2x00_probe_one+0xa3a/0x1b80 [qla2xxx]
[ 12.377617] ? _raw_spin_lock_irqsave+0x19/0x40
[ 12.384284] local_pci_probe+0x42/0x80
[ 12.390162] ? pci_match_device+0xd7/0x110
[ 12.396366] pci_device_probe+0xfd/0x1b0
[ 12.402372] really_probe+0x1e7/0x3e0
[ 12.408114] __driver_probe_device+0xfe/0x180
[ 12.414544] driver_probe_device+0x1e/0x90
[ 12.420685] __driver_attach+0xc0/0x1c0
[ 12.426536] ? __device_attach_driver+0xe0/0xe0
[ 12.433061] ? __device_attach_driver+0xe0/0xe0
[ 12.439538] bus_for_each_dev+0x78/0xc0
[ 12.445294] bus_add_driver+0x12b/0x1e0
[ 12.451021] driver_register+0x8f/0xe0
[ 12.456631] ? 0xffffffffc07bc000
[ 12.461773] qla2x00_module_init+0x1be/0x229 [qla2xxx]
[ 12.468776] do_one_initcall+0x44/0x200
[ 12.474401] ? load_module+0xad3/0xba0
[ 12.479908] ? kmem_cache_alloc_trace+0x45/0x410
[ 12.486268] do_init_module+0x5c/0x280
[ 12.491730] __do_sys_init_module+0x12e/0x1b0
[ 12.497785] do_syscall_64+0x3b/0x90
[ 12.503029] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 12.509764] RIP: 0033:0x7f554f73ab2e |
| In the Linux kernel, the following vulnerability has been resolved:
x86/mce: Work around an erratum on fast string copy instructions
A rare kernel panic scenario can happen when the following conditions
are met due to an erratum on fast string copy instructions:
1) An uncorrected error.
2) That error must be in first cache line of a page.
3) Kernel must execute page_copy from the page immediately before that
page.
The fast string copy instructions ("REP; MOVS*") could consume an
uncorrectable memory error in the cache line _right after_ the desired
region to copy and raise an MCE.
Bit 0 of MSR_IA32_MISC_ENABLE can be cleared to disable fast string
copy and will avoid such spurious machine checks. However, that is less
preferable due to the permanent performance impact. Considering memory
poison is rare, it's desirable to keep fast string copy enabled until an
MCE is seen.
Intel has confirmed the following:
1. The CPU erratum of fast string copy only applies to Skylake,
Cascade Lake and Cooper Lake generations.
Directly return from the MCE handler:
2. Will result in complete execution of the "REP; MOVS*" with no data
loss or corruption.
3. Will not result in another MCE firing on the next poisoned cache line
due to "REP; MOVS*".
4. Will resume execution from a correct point in code.
5. Will result in the same instruction that triggered the MCE firing a
second MCE immediately for any other software recoverable data fetch
errors.
6. Is not safe without disabling the fast string copy, as the next fast
string copy of the same buffer on the same CPU would result in a PANIC
MCE.
This should mitigate the erratum completely with the only caveat that
the fast string copy is disabled on the affected hyper thread thus
performance degradation.
This is still better than the OS crashing on MCEs raised on an
irrelevant process due to "REP; MOVS*' accesses in a kernel context,
e.g., copy_page.
Injected errors on 1st cache line of 8 anonymous pages of process
'proc1' and observed MCE consumption from 'proc2' with no panic
(directly returned).
Without the fix, the host panicked within a few minutes on a
random 'proc2' process due to kernel access from copy_page.
[ bp: Fix comment style + touch ups, zap an unlikely(), improve the
quirk function's readability. ] |
| In the Linux kernel, the following vulnerability has been resolved:
dm ioctl: prevent potential spectre v1 gadget
It appears like cmd could be a Spectre v1 gadget as it's supplied by a
user and used as an array index. Prevent the contents of kernel memory
from being leaked to userspace via speculative execution by using
array_index_nospec. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: conntrack: revisit gc autotuning
as of commit 4608fdfc07e1
("netfilter: conntrack: collect all entries in one cycle")
conntrack gc was changed to run every 2 minutes.
On systems where conntrack hash table is set to large value, most evictions
happen from gc worker rather than the packet path due to hash table
distribution.
This causes netlink event overflows when events are collected.
This change collects average expiry of scanned entries and
reschedules to the average remaining value, within 1 to 60 second interval.
To avoid event overflows, reschedule after each bucket and add a
limit for both run time and number of evictions per run.
If more entries have to be evicted, reschedule and restart 1 jiffy
into the future. |
| In the Linux kernel, the following vulnerability has been resolved:
virtio_console: eliminate anonymous module_init & module_exit
Eliminate anonymous module_init() and module_exit(), which can lead to
confusion or ambiguity when reading System.map, crashes/oops/bugs,
or an initcall_debug log.
Give each of these init and exit functions unique driver-specific
names to eliminate the anonymous names.
Example 1: (System.map)
ffffffff832fc78c t init
ffffffff832fc79e t init
ffffffff832fc8f8 t init
Example 2: (initcall_debug log)
calling init+0x0/0x12 @ 1
initcall init+0x0/0x12 returned 0 after 15 usecs
calling init+0x0/0x60 @ 1
initcall init+0x0/0x60 returned 0 after 2 usecs
calling init+0x0/0x9a @ 1
initcall init+0x0/0x9a returned 0 after 74 usecs |
| In the Linux kernel, the following vulnerability has been resolved:
powerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit
mpe: On 64-bit Book3E vmalloc space starts at 0x8000000000000000.
Because of the way __pa() works we have:
__pa(0x8000000000000000) == 0, and therefore
virt_to_pfn(0x8000000000000000) == 0, and therefore
virt_addr_valid(0x8000000000000000) == true
Which is wrong, virt_addr_valid() should be false for vmalloc space.
In fact all vmalloc addresses that alias with a valid PFN will return
true from virt_addr_valid(). That can cause bugs with hardened usercopy
as described below by Kefeng Wang:
When running ethtool eth0 on 64-bit Book3E, a BUG occurred:
usercopy: Kernel memory exposure attempt detected from SLUB object not in SLUB page?! (offset 0, size 1048)!
kernel BUG at mm/usercopy.c:99
...
usercopy_abort+0x64/0xa0 (unreliable)
__check_heap_object+0x168/0x190
__check_object_size+0x1a0/0x200
dev_ethtool+0x2494/0x2b20
dev_ioctl+0x5d0/0x770
sock_do_ioctl+0xf0/0x1d0
sock_ioctl+0x3ec/0x5a0
__se_sys_ioctl+0xf0/0x160
system_call_exception+0xfc/0x1f0
system_call_common+0xf8/0x200
The code shows below,
data = vzalloc(array_size(gstrings.len, ETH_GSTRING_LEN));
copy_to_user(useraddr, data, gstrings.len * ETH_GSTRING_LEN))
The data is alloced by vmalloc(), virt_addr_valid(ptr) will return true
on 64-bit Book3E, which leads to the panic.
As commit 4dd7554a6456 ("powerpc/64: Add VIRTUAL_BUG_ON checks for __va
and __pa addresses") does, make sure the virt addr above PAGE_OFFSET in
the virt_addr_valid() for 64-bit, also add upper limit check to make
sure the virt is below high_memory.
Meanwhile, for 32-bit PAGE_OFFSET is the virtual address of the start
of lowmem, high_memory is the upper low virtual address, the check is
suitable for 32-bit, this will fix the issue mentioned in commit
602946ec2f90 ("powerpc: Set max_mapnr correctly") too.
On 32-bit there is a similar problem with high memory, that was fixed in
commit 602946ec2f90 ("powerpc: Set max_mapnr correctly"), but that
commit breaks highmem and needs to be reverted.
We can't easily fix __pa(), we have code that relies on its current
behaviour. So for now add extra checks to virt_addr_valid().
For 64-bit Book3S the extra checks are not necessary, the combination of
virt_to_pfn() and pfn_valid() should yield the correct result, but they
are harmless.
[mpe: Add additional change log detail] |
| In the Linux kernel, the following vulnerability has been resolved:
Drivers: hv: vmbus: Deactivate sysctl_record_panic_msg by default in isolated guests
hv_panic_page might contain guest-sensitive information, do not dump it
over to Hyper-V by default in isolated guests.
While at it, update some comments in hyperv_{panic,die}_event(). |
| In the Linux kernel, the following vulnerability has been resolved:
sh: cpuinfo: Fix a warning for CONFIG_CPUMASK_OFFSTACK
When CONFIG_CPUMASK_OFFSTACK and CONFIG_DEBUG_PER_CPU_MAPS are selected,
cpu_max_bits_warn() generates a runtime warning similar as below when
showing /proc/cpuinfo. Fix this by using nr_cpu_ids (the runtime limit)
instead of NR_CPUS to iterate CPUs.
[ 3.052463] ------------[ cut here ]------------
[ 3.059679] WARNING: CPU: 3 PID: 1 at include/linux/cpumask.h:108 show_cpuinfo+0x5e8/0x5f0
[ 3.070072] Modules linked in: efivarfs autofs4
[ 3.076257] CPU: 0 PID: 1 Comm: systemd Not tainted 5.19-rc5+ #1052
[ 3.099465] Stack : 9000000100157b08 9000000000f18530 9000000000cf846c 9000000100154000
[ 3.109127] 9000000100157a50 0000000000000000 9000000100157a58 9000000000ef7430
[ 3.118774] 90000001001578e8 0000000000000040 0000000000000020 ffffffffffffffff
[ 3.128412] 0000000000aaaaaa 1ab25f00eec96a37 900000010021de80 900000000101c890
[ 3.138056] 0000000000000000 0000000000000000 0000000000000000 0000000000aaaaaa
[ 3.147711] ffff8000339dc220 0000000000000001 0000000006ab4000 0000000000000000
[ 3.157364] 900000000101c998 0000000000000004 9000000000ef7430 0000000000000000
[ 3.167012] 0000000000000009 000000000000006c 0000000000000000 0000000000000000
[ 3.176641] 9000000000d3de08 9000000001639390 90000000002086d8 00007ffff0080286
[ 3.186260] 00000000000000b0 0000000000000004 0000000000000000 0000000000071c1c
[ 3.195868] ...
[ 3.199917] Call Trace:
[ 3.203941] [<90000000002086d8>] show_stack+0x38/0x14c
[ 3.210666] [<9000000000cf846c>] dump_stack_lvl+0x60/0x88
[ 3.217625] [<900000000023d268>] __warn+0xd0/0x100
[ 3.223958] [<9000000000cf3c90>] warn_slowpath_fmt+0x7c/0xcc
[ 3.231150] [<9000000000210220>] show_cpuinfo+0x5e8/0x5f0
[ 3.238080] [<90000000004f578c>] seq_read_iter+0x354/0x4b4
[ 3.245098] [<90000000004c2e90>] new_sync_read+0x17c/0x1c4
[ 3.252114] [<90000000004c5174>] vfs_read+0x138/0x1d0
[ 3.258694] [<90000000004c55f8>] ksys_read+0x70/0x100
[ 3.265265] [<9000000000cfde9c>] do_syscall+0x7c/0x94
[ 3.271820] [<9000000000202fe4>] handle_syscall+0xc4/0x160
[ 3.281824] ---[ end trace 8b484262b4b8c24c ]--- |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: qgroup: fix sleep from invalid context bug in btrfs_qgroup_inherit()
Syzkaller reported BUG as follows:
BUG: sleeping function called from invalid context at
include/linux/sched/mm.h:274
Call Trace:
<TASK>
dump_stack_lvl+0xcd/0x134
__might_resched.cold+0x222/0x26b
kmem_cache_alloc+0x2e7/0x3c0
update_qgroup_limit_item+0xe1/0x390
btrfs_qgroup_inherit+0x147b/0x1ee0
create_subvol+0x4eb/0x1710
btrfs_mksubvol+0xfe5/0x13f0
__btrfs_ioctl_snap_create+0x2b0/0x430
btrfs_ioctl_snap_create_v2+0x25a/0x520
btrfs_ioctl+0x2a1c/0x5ce0
__x64_sys_ioctl+0x193/0x200
do_syscall_64+0x35/0x80
Fix this by calling qgroup_dirty() on @dstqgroup, and update limit item in
btrfs_run_qgroups() later outside of the spinlock context. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: seq: Fix function prototype mismatch in snd_seq_expand_var_event
With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
indirect call targets are validated against the expected function
pointer prototype to make sure the call target is valid to help mitigate
ROP attacks. If they are not identical, there is a failure at run time,
which manifests as either a kernel panic or thread getting killed.
seq_copy_in_user() and seq_copy_in_kernel() did not have prototypes
matching snd_seq_dump_func_t. Adjust this and remove the casts. There
are not resulting binary output differences.
This was found as a result of Clang's new -Wcast-function-type-strict
flag, which is more sensitive than the simpler -Wcast-function-type,
which only checks for type width mismatches. |
| In the Linux kernel, the following vulnerability has been resolved:
udf: Fix preallocation discarding at indirect extent boundary
When preallocation extent is the first one in the extent block, the
code would corrupt extent tree header instead. Fix the problem and use
udf_delete_aext() for deleting extent to avoid some code duplication. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: x86/mmu: make apf token non-zero to fix bug
In current async pagefault logic, when a page is ready, KVM relies on
kvm_arch_can_dequeue_async_page_present() to determine whether to deliver
a READY event to the Guest. This function test token value of struct
kvm_vcpu_pv_apf_data, which must be reset to zero by Guest kernel when a
READY event is finished by Guest. If value is zero meaning that a READY
event is done, so the KVM can deliver another.
But the kvm_arch_setup_async_pf() may produce a valid token with zero
value, which is confused with previous mention and may lead the loss of
this READY event.
This bug may cause task blocked forever in Guest:
INFO: task stress:7532 blocked for more than 1254 seconds.
Not tainted 5.10.0 #16
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:stress state:D stack: 0 pid: 7532 ppid: 1409
flags:0x00000080
Call Trace:
__schedule+0x1e7/0x650
schedule+0x46/0xb0
kvm_async_pf_task_wait_schedule+0xad/0xe0
? exit_to_user_mode_prepare+0x60/0x70
__kvm_handle_async_pf+0x4f/0xb0
? asm_exc_page_fault+0x8/0x30
exc_page_fault+0x6f/0x110
? asm_exc_page_fault+0x8/0x30
asm_exc_page_fault+0x1e/0x30
RIP: 0033:0x402d00
RSP: 002b:00007ffd31912500 EFLAGS: 00010206
RAX: 0000000000071000 RBX: ffffffffffffffff RCX: 00000000021a32b0
RDX: 000000000007d011 RSI: 000000000007d000 RDI: 00000000021262b0
RBP: 00000000021262b0 R08: 0000000000000003 R09: 0000000000000086
R10: 00000000000000eb R11: 00007fefbdf2baa0 R12: 0000000000000000
R13: 0000000000000002 R14: 000000000007d000 R15: 0000000000001000 |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: do not WARN_ON() if we have PageError set
Whenever we do any extent buffer operations we call
assert_eb_page_uptodate() to complain loudly if we're operating on an
non-uptodate page. Our overnight tests caught this warning earlier this
week
WARNING: CPU: 1 PID: 553508 at fs/btrfs/extent_io.c:6849 assert_eb_page_uptodate+0x3f/0x50
CPU: 1 PID: 553508 Comm: kworker/u4:13 Tainted: G W 5.17.0-rc3+ #564
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Workqueue: btrfs-cache btrfs_work_helper
RIP: 0010:assert_eb_page_uptodate+0x3f/0x50
RSP: 0018:ffffa961440a7c68 EFLAGS: 00010246
RAX: 0017ffffc0002112 RBX: ffffe6e74453f9c0 RCX: 0000000000001000
RDX: ffffe6e74467c887 RSI: ffffe6e74453f9c0 RDI: ffff8d4c5efc2fc0
RBP: 0000000000000d56 R08: ffff8d4d4a224000 R09: 0000000000000000
R10: 00015817fa9d1ef0 R11: 000000000000000c R12: 00000000000007b1
R13: ffff8d4c5efc2fc0 R14: 0000000001500000 R15: 0000000001cb1000
FS: 0000000000000000(0000) GS:ffff8d4dbbd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff31d3448d8 CR3: 0000000118be8004 CR4: 0000000000370ee0
Call Trace:
extent_buffer_test_bit+0x3f/0x70
free_space_test_bit+0xa6/0xc0
load_free_space_tree+0x1f6/0x470
caching_thread+0x454/0x630
? rcu_read_lock_sched_held+0x12/0x60
? rcu_read_lock_sched_held+0x12/0x60
? rcu_read_lock_sched_held+0x12/0x60
? lock_release+0x1f0/0x2d0
btrfs_work_helper+0xf2/0x3e0
? lock_release+0x1f0/0x2d0
? finish_task_switch.isra.0+0xf9/0x3a0
process_one_work+0x26d/0x580
? process_one_work+0x580/0x580
worker_thread+0x55/0x3b0
? process_one_work+0x580/0x580
kthread+0xf0/0x120
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x1f/0x30
This was partially fixed by c2e39305299f01 ("btrfs: clear extent buffer
uptodate when we fail to write it"), however all that fix did was keep
us from finding extent buffers after a failed writeout. It didn't keep
us from continuing to use a buffer that we already had found.
In this case we're searching the commit root to cache the block group,
so we can start committing the transaction and switch the commit root
and then start writing. After the switch we can look up an extent
buffer that hasn't been written yet and start processing that block
group. Then we fail to write that block out and clear Uptodate on the
page, and then we start spewing these errors.
Normally we're protected by the tree lock to a certain degree here. If
we read a block we have that block read locked, and we block the writer
from locking the block before we submit it for the write. However this
isn't necessarily fool proof because the read could happen before we do
the submit_bio and after we locked and unlocked the extent buffer.
Also in this particular case we have path->skip_locking set, so that
won't save us here. We'll simply get a block that was valid when we
read it, but became invalid while we were using it.
What we really want is to catch the case where we've "read" a block but
it's not marked Uptodate. On read we ClearPageError(), so if we're
!Uptodate and !Error we know we didn't do the right thing for reading
the page.
Fix this by checking !Uptodate && !Error, this way we will not complain
if our buffer gets invalidated while we're using it, and we'll maintain
the spirit of the check which is to make sure we have a fully in-cache
block while we're messing with it. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: do not start relocation until in progress drops are done
We hit a bug with a recovering relocation on mount for one of our file
systems in production. I reproduced this locally by injecting errors
into snapshot delete with balance running at the same time. This
presented as an error while looking up an extent item
WARNING: CPU: 5 PID: 1501 at fs/btrfs/extent-tree.c:866 lookup_inline_extent_backref+0x647/0x680
CPU: 5 PID: 1501 Comm: btrfs-balance Not tainted 5.16.0-rc8+ #8
RIP: 0010:lookup_inline_extent_backref+0x647/0x680
RSP: 0018:ffffae0a023ab960 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 000000000000000c RDI: 0000000000000000
RBP: ffff943fd2a39b60 R08: 0000000000000000 R09: 0000000000000001
R10: 0001434088152de0 R11: 0000000000000000 R12: 0000000001d05000
R13: ffff943fd2a39b60 R14: ffff943fdb96f2a0 R15: ffff9442fc923000
FS: 0000000000000000(0000) GS:ffff944e9eb40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1157b1fca8 CR3: 000000010f092000 CR4: 0000000000350ee0
Call Trace:
<TASK>
insert_inline_extent_backref+0x46/0xd0
__btrfs_inc_extent_ref.isra.0+0x5f/0x200
? btrfs_merge_delayed_refs+0x164/0x190
__btrfs_run_delayed_refs+0x561/0xfa0
? btrfs_search_slot+0x7b4/0xb30
? btrfs_update_root+0x1a9/0x2c0
btrfs_run_delayed_refs+0x73/0x1f0
? btrfs_update_root+0x1a9/0x2c0
btrfs_commit_transaction+0x50/0xa50
? btrfs_update_reloc_root+0x122/0x220
prepare_to_merge+0x29f/0x320
relocate_block_group+0x2b8/0x550
btrfs_relocate_block_group+0x1a6/0x350
btrfs_relocate_chunk+0x27/0xe0
btrfs_balance+0x777/0xe60
balance_kthread+0x35/0x50
? btrfs_balance+0xe60/0xe60
kthread+0x16b/0x190
? set_kthread_struct+0x40/0x40
ret_from_fork+0x22/0x30
</TASK>
Normally snapshot deletion and relocation are excluded from running at
the same time by the fs_info->cleaner_mutex. However if we had a
pending balance waiting to get the ->cleaner_mutex, and a snapshot
deletion was running, and then the box crashed, we would come up in a
state where we have a half deleted snapshot.
Again, in the normal case the snapshot deletion needs to complete before
relocation can start, but in this case relocation could very well start
before the snapshot deletion completes, as we simply add the root to the
dead roots list and wait for the next time the cleaner runs to clean up
the snapshot.
Fix this by setting a bit on the fs_info if we have any DEAD_ROOT's that
had a pending drop_progress key. If they do then we know we were in the
middle of the drop operation and set a flag on the fs_info. Then
balance can wait until this flag is cleared to start up again.
If there are DEAD_ROOT's that don't have a drop_progress set then we're
safe to start balance right away as we'll be properly protected by the
cleaner_mutex. |
