| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
tls: fix use-after-free on failed backlog decryption
When the decrypt request goes to the backlog and crypto_aead_decrypt
returns -EBUSY, tls_do_decryption will wait until all async
decryptions have completed. If one of them fails, tls_do_decryption
will return -EBADMSG and tls_decrypt_sg jumps to the error path,
releasing all the pages. But the pages have been passed to the async
callback, and have already been released by tls_decrypt_done.
The only true async case is when crypto_aead_decrypt returns
-EINPROGRESS. With -EBUSY, we already waited so we can tell
tls_sw_recvmsg that the data is available for immediate copy, but we
need to notify tls_decrypt_sg (via the new ->async_done flag) that the
memory has already been released. |
| A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation.
Addition and removal of rules from chain bindings within the same transaction causes leads to use-after-free.
We recommend upgrading past commit f15f29fd4779be8a418b66e9d52979bb6d6c2325. |
| Path Traversal in the log file retrieval function in Canonical LXD 5.0 LTS on Linux allows authenticated remote attackers to read arbitrary files on the host system via crafted log file names or symbolic links. |
| In the Linux kernel, the following vulnerability has been resolved:
ptp: ocp: Fix a resource leak in an error handling path
If an error occurs after a successful 'pci_ioremap_bar()' call, it must be
undone by a corresponding 'pci_iounmap()' call, as already done in the
remove function. |
| In the Linux kernel, the following vulnerability has been resolved:
dm: don't attempt to queue IO under RCU protection
dm looks up the table for IO based on the request type, with an
assumption that if the request is marked REQ_NOWAIT, it's fine to
attempt to submit that IO while under RCU read lock protection. This
is not OK, as REQ_NOWAIT just means that we should not be sleeping
waiting on other IO, it does not mean that we can't potentially
schedule.
A simple test case demonstrates this quite nicely:
int main(int argc, char *argv[])
{
struct iovec iov;
int fd;
fd = open("/dev/dm-0", O_RDONLY | O_DIRECT);
posix_memalign(&iov.iov_base, 4096, 4096);
iov.iov_len = 4096;
preadv2(fd, &iov, 1, 0, RWF_NOWAIT);
return 0;
}
which will instantly spew:
BUG: sleeping function called from invalid context at include/linux/sched/mm.h:306
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 5580, name: dm-nowait
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
INFO: lockdep is turned off.
CPU: 7 PID: 5580 Comm: dm-nowait Not tainted 6.6.0-rc1-g39956d2dcd81 #132
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x11d/0x1b0
__might_resched+0x3c3/0x5e0
? preempt_count_sub+0x150/0x150
mempool_alloc+0x1e2/0x390
? mempool_resize+0x7d0/0x7d0
? lock_sync+0x190/0x190
? lock_release+0x4b7/0x670
? internal_get_user_pages_fast+0x868/0x2d40
bio_alloc_bioset+0x417/0x8c0
? bvec_alloc+0x200/0x200
? internal_get_user_pages_fast+0xb8c/0x2d40
bio_alloc_clone+0x53/0x100
dm_submit_bio+0x27f/0x1a20
? lock_release+0x4b7/0x670
? blk_try_enter_queue+0x1a0/0x4d0
? dm_dax_direct_access+0x260/0x260
? rcu_is_watching+0x12/0xb0
? blk_try_enter_queue+0x1cc/0x4d0
__submit_bio+0x239/0x310
? __bio_queue_enter+0x700/0x700
? kvm_clock_get_cycles+0x40/0x60
? ktime_get+0x285/0x470
submit_bio_noacct_nocheck+0x4d9/0xb80
? should_fail_request+0x80/0x80
? preempt_count_sub+0x150/0x150
? lock_release+0x4b7/0x670
? __bio_add_page+0x143/0x2d0
? iov_iter_revert+0x27/0x360
submit_bio_noacct+0x53e/0x1b30
submit_bio_wait+0x10a/0x230
? submit_bio_wait_endio+0x40/0x40
__blkdev_direct_IO_simple+0x4f8/0x780
? blkdev_bio_end_io+0x4c0/0x4c0
? stack_trace_save+0x90/0xc0
? __bio_clone+0x3c0/0x3c0
? lock_release+0x4b7/0x670
? lock_sync+0x190/0x190
? atime_needs_update+0x3bf/0x7e0
? timestamp_truncate+0x21b/0x2d0
? inode_owner_or_capable+0x240/0x240
blkdev_direct_IO.part.0+0x84a/0x1810
? rcu_is_watching+0x12/0xb0
? lock_release+0x4b7/0x670
? blkdev_read_iter+0x40d/0x530
? reacquire_held_locks+0x4e0/0x4e0
? __blkdev_direct_IO_simple+0x780/0x780
? rcu_is_watching+0x12/0xb0
? __mark_inode_dirty+0x297/0xd50
? preempt_count_add+0x72/0x140
blkdev_read_iter+0x2a4/0x530
do_iter_readv_writev+0x2f2/0x3c0
? generic_copy_file_range+0x1d0/0x1d0
? fsnotify_perm.part.0+0x25d/0x630
? security_file_permission+0xd8/0x100
do_iter_read+0x31b/0x880
? import_iovec+0x10b/0x140
vfs_readv+0x12d/0x1a0
? vfs_iter_read+0xb0/0xb0
? rcu_is_watching+0x12/0xb0
? rcu_is_watching+0x12/0xb0
? lock_release+0x4b7/0x670
do_preadv+0x1b3/0x260
? do_readv+0x370/0x370
__x64_sys_preadv2+0xef/0x150
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f5af41ad806
Code: 41 54 41 89 fc 55 44 89 c5 53 48 89 cb 48 83 ec 18 80 3d e4 dd 0d 00 00 74 7a 45 89 c1 49 89 ca 45 31 c0 b8 47 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 be 00 00 00 48 85 c0 79 4a 48 8b 0d da 55
RSP: 002b:00007ffd3145c7f0 EFLAGS: 00000246 ORIG_RAX: 0000000000000147
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5af41ad806
RDX: 0000000000000001 RSI: 00007ffd3145c850 RDI: 0000000000000003
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007ffd3145c850 R14: 000055f5f0431dd8 R15: 0000000000000001
</TASK>
where in fact it is
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: fix deadlock due to mbcache entry corruption
When manipulating xattr blocks, we can deadlock infinitely looping
inside ext4_xattr_block_set() where we constantly keep finding xattr
block for reuse in mbcache but we are unable to reuse it because its
reference count is too big. This happens because cache entry for the
xattr block is marked as reusable (e_reusable set) although its
reference count is too big. When this inconsistency happens, this
inconsistent state is kept indefinitely and so ext4_xattr_block_set()
keeps retrying indefinitely.
The inconsistent state is caused by non-atomic update of e_reusable bit.
e_reusable is part of a bitfield and e_reusable update can race with
update of e_referenced bit in the same bitfield resulting in loss of one
of the updates. Fix the problem by using atomic bitops instead.
This bug has been around for many years, but it became *much* easier
to hit after commit 65f8b80053a1 ("ext4: fix race when reusing xattr
blocks"). |
| In the Linux kernel, the following vulnerability has been resolved:
misc: ocxl: fix possible name leak in ocxl_file_register_afu()
If device_register() returns error in ocxl_file_register_afu(),
the name allocated by dev_set_name() need be freed. As comment
of device_register() says, it should use put_device() to give
up the reference in the error path. So fix this by calling
put_device(), then the name can be freed in kobject_cleanup(),
and info is freed in info_release(). |
| In the Linux kernel, the following vulnerability has been resolved:
mmc: core: Fix kernel panic when remove non-standard SDIO card
SDIO tuple is only allocated for standard SDIO card, especially it causes
memory corruption issues when the non-standard SDIO card has removed, which
is because the card device's reference counter does not increase for it at
sdio_init_func(), but all SDIO card device reference counter gets decreased
at sdio_release_func(). |
| In the Linux kernel, the following vulnerability has been resolved:
mmc: omap_hsmmc: fix return value check of mmc_add_host()
mmc_add_host() may return error, if we ignore its return value,
it will lead two issues:
1. The memory that allocated in mmc_alloc_host() is leaked.
2. In the remove() path, mmc_remove_host() will be called to
delete device, but it's not added yet, it will lead a kernel
crash because of null-ptr-deref in device_del().
Fix this by checking the return value and goto error path wihch
will call mmc_free_host(). |
| In the Linux kernel, the following vulnerability has been resolved:
mailbox: zynq-ipi: fix error handling while device_register() fails
If device_register() fails, it has two issues:
1. The name allocated by dev_set_name() is leaked.
2. The parent of device is not NULL, device_unregister() is called
in zynqmp_ipi_free_mboxes(), it will lead a kernel crash because
of removing not added device.
Call put_device() to give up the reference, so the name is freed in
kobject_cleanup(). Add device registered check in zynqmp_ipi_free_mboxes()
to avoid null-ptr-deref. |
| In the Linux kernel, the following vulnerability has been resolved:
net: rds: don't hold sock lock when cancelling work from rds_tcp_reset_callbacks()
syzbot is reporting lockdep warning at rds_tcp_reset_callbacks() [1], for
commit ac3615e7f3cffe2a ("RDS: TCP: Reduce code duplication in
rds_tcp_reset_callbacks()") added cancel_delayed_work_sync() into a section
protected by lock_sock() without realizing that rds_send_xmit() might call
lock_sock().
We don't need to protect cancel_delayed_work_sync() using lock_sock(), for
even if rds_{send,recv}_worker() re-queued this work while __flush_work()
from cancel_delayed_work_sync() was waiting for this work to complete,
retried rds_{send,recv}_worker() is no-op due to the absence of RDS_CONN_UP
bit. |
| In the Linux kernel, the following vulnerability has been resolved:
ip6_vti: fix slab-use-after-free in decode_session6
When ipv6_vti device is set to the qdisc of the sfb type, the cb field
of the sent skb may be modified during enqueuing. Then,
slab-use-after-free may occur when ipv6_vti device sends IPv6 packets.
The stack information is as follows:
BUG: KASAN: slab-use-after-free in decode_session6+0x103f/0x1890
Read of size 1 at addr ffff88802e08edc2 by task swapper/0/0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.4.0-next-20230707-00001-g84e2cad7f979 #410
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl+0xd9/0x150
print_address_description.constprop.0+0x2c/0x3c0
kasan_report+0x11d/0x130
decode_session6+0x103f/0x1890
__xfrm_decode_session+0x54/0xb0
vti6_tnl_xmit+0x3e6/0x1ee0
dev_hard_start_xmit+0x187/0x700
sch_direct_xmit+0x1a3/0xc30
__qdisc_run+0x510/0x17a0
__dev_queue_xmit+0x2215/0x3b10
neigh_connected_output+0x3c2/0x550
ip6_finish_output2+0x55a/0x1550
ip6_finish_output+0x6b9/0x1270
ip6_output+0x1f1/0x540
ndisc_send_skb+0xa63/0x1890
ndisc_send_rs+0x132/0x6f0
addrconf_rs_timer+0x3f1/0x870
call_timer_fn+0x1a0/0x580
expire_timers+0x29b/0x4b0
run_timer_softirq+0x326/0x910
__do_softirq+0x1d4/0x905
irq_exit_rcu+0xb7/0x120
sysvec_apic_timer_interrupt+0x97/0xc0
</IRQ>
Allocated by task 9176:
kasan_save_stack+0x22/0x40
kasan_set_track+0x25/0x30
__kasan_slab_alloc+0x7f/0x90
kmem_cache_alloc_node+0x1cd/0x410
kmalloc_reserve+0x165/0x270
__alloc_skb+0x129/0x330
netlink_sendmsg+0x9b1/0xe30
sock_sendmsg+0xde/0x190
____sys_sendmsg+0x739/0x920
___sys_sendmsg+0x110/0x1b0
__sys_sendmsg+0xf7/0x1c0
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Freed by task 9176:
kasan_save_stack+0x22/0x40
kasan_set_track+0x25/0x30
kasan_save_free_info+0x2b/0x40
____kasan_slab_free+0x160/0x1c0
slab_free_freelist_hook+0x11b/0x220
kmem_cache_free+0xf0/0x490
skb_free_head+0x17f/0x1b0
skb_release_data+0x59c/0x850
consume_skb+0xd2/0x170
netlink_unicast+0x54f/0x7f0
netlink_sendmsg+0x926/0xe30
sock_sendmsg+0xde/0x190
____sys_sendmsg+0x739/0x920
___sys_sendmsg+0x110/0x1b0
__sys_sendmsg+0xf7/0x1c0
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
The buggy address belongs to the object at ffff88802e08ed00
which belongs to the cache skbuff_small_head of size 640
The buggy address is located 194 bytes inside of
freed 640-byte region [ffff88802e08ed00, ffff88802e08ef80)
As commit f855691975bb ("xfrm6: Fix the nexthdr offset in
_decode_session6.") showed, xfrm_decode_session was originally intended
only for the receive path. IP6CB(skb)->nhoff is not set during
transmission. Therefore, set the cb field in the skb to 0 before
sending packets. |
| In the Linux kernel, the following vulnerability has been resolved:
platform/x86: think-lmi: Fix memory leak when showing current settings
When retriving a item string with tlmi_setting(), the result has to be
freed using kfree(). In current_value_show() however, malformed
item strings are not freed, causing a memory leak.
Fix this by eliminating the early return responsible for this. |
| In the Linux kernel, the following vulnerability has been resolved:
net: read sk->sk_family once in sk_mc_loop()
syzbot is playing with IPV6_ADDRFORM quite a lot these days,
and managed to hit the WARN_ON_ONCE(1) in sk_mc_loop()
We have many more similar issues to fix.
WARNING: CPU: 1 PID: 1593 at net/core/sock.c:782 sk_mc_loop+0x165/0x260
Modules linked in:
CPU: 1 PID: 1593 Comm: kworker/1:3 Not tainted 6.1.40-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events_power_efficient gc_worker
RIP: 0010:sk_mc_loop+0x165/0x260 net/core/sock.c:782
Code: 34 1b fd 49 81 c7 18 05 00 00 4c 89 f8 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 ff e8 25 36 6d fd 4d 8b 37 eb 13 e8 db 33 1b fd <0f> 0b b3 01 eb 34 e8 d0 33 1b fd 45 31 f6 49 83 c6 38 4c 89 f0 48
RSP: 0018:ffffc90000388530 EFLAGS: 00010246
RAX: ffffffff846d9b55 RBX: 0000000000000011 RCX: ffff88814f884980
RDX: 0000000000000102 RSI: ffffffff87ae5160 RDI: 0000000000000011
RBP: ffffc90000388550 R08: 0000000000000003 R09: ffffffff846d9a65
R10: 0000000000000002 R11: ffff88814f884980 R12: dffffc0000000000
R13: ffff88810dbee000 R14: 0000000000000010 R15: ffff888150084000
FS: 0000000000000000(0000) GS:ffff8881f6b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000180 CR3: 000000014ee5b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
[<ffffffff8507734f>] ip6_finish_output2+0x33f/0x1ae0 net/ipv6/ip6_output.c:83
[<ffffffff85062766>] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[<ffffffff85062766>] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[<ffffffff85061f8c>] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[<ffffffff85061f8c>] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[<ffffffff852071cf>] dst_output include/net/dst.h:444 [inline]
[<ffffffff852071cf>] ip6_local_out+0x10f/0x140 net/ipv6/output_core.c:161
[<ffffffff83618fb4>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:483 [inline]
[<ffffffff83618fb4>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff83618fb4>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff83618fb4>] ipvlan_queue_xmit+0x1174/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff8361ddd9>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84763fc0>] netdev_start_xmit include/linux/netdevice.h:4925 [inline]
[<ffffffff84763fc0>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84763fc0>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff8494c650>] sch_direct_xmit+0x2a0/0x9c0 net/sched/sch_generic.c:342
[<ffffffff8494d883>] qdisc_restart net/sched/sch_generic.c:407 [inline]
[<ffffffff8494d883>] __qdisc_run+0xb13/0x1e70 net/sched/sch_generic.c:415
[<ffffffff8478c426>] qdisc_run+0xd6/0x260 include/net/pkt_sched.h:125
[<ffffffff84796eac>] net_tx_action+0x7ac/0x940 net/core/dev.c:5247
[<ffffffff858002bd>] __do_softirq+0x2bd/0x9bd kernel/softirq.c:599
[<ffffffff814c3fe8>] invoke_softirq kernel/softirq.c:430 [inline]
[<ffffffff814c3fe8>] __irq_exit_rcu+0xc8/0x170 kernel/softirq.c:683
[<ffffffff814c3f09>] irq_exit_rcu+0x9/0x20 kernel/softirq.c:695 |
| In the Linux kernel, the following vulnerability has been resolved:
regulator: da9063: fix null pointer deref with partial DT config
When some of the da9063 regulators do not have corresponding DT nodes
a null pointer dereference occurs on boot because such regulators have
no init_data causing the pointers calculated in
da9063_check_xvp_constraints() to be invalid.
Do not dereference them in this case. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: ath9k: htc_hst: free skb in ath9k_htc_rx_msg() if there is no callback function
It is stated that ath9k_htc_rx_msg() either frees the provided skb or
passes its management to another callback function. However, the skb is
not freed in case there is no another callback function, and Syzkaller was
able to cause a memory leak. Also minor comment fix.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller. |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: fix rbtree traversal bug in ext4_mb_use_preallocated
During allocations, while looking for preallocations(PA) in the per
inode rbtree, we can't do a direct traversal of the tree because
ext4_mb_discard_group_preallocation() can paralelly mark the pa deleted
and that can cause direct traversal to skip some entries. This was
leading to a BUG_ON() being hit [1] when we missed a PA that could satisfy
our request and ultimately tried to create a new PA that would overlap
with the missed one.
To makes sure we handle that case while still keeping the performance of
the rbtree, we make use of the fact that the only pa that could possibly
overlap the original goal start is the one that satisfies the below
conditions:
1. It must have it's logical start immediately to the left of
(ie less than) original logical start.
2. It must not be deleted
To find this pa we use the following traversal method:
1. Descend into the rbtree normally to find the immediate neighboring
PA. Here we keep descending irrespective of if the PA is deleted or if
it overlaps with our request etc. The goal is to find an immediately
adjacent PA.
2. If the found PA is on right of original goal, use rb_prev() to find
the left adjacent PA.
3. Check if this PA is deleted and keep moving left with rb_prev() until
a non deleted PA is found.
4. This is the PA we are looking for. Now we can check if it can satisfy
the original request and proceed accordingly.
This approach also takes care of having deleted PAs in the tree.
(While we are at it, also fix a possible overflow bug in calculating the
end of a PA)
[1] https://lore.kernel.org/linux-ext4/CA+G9fYv2FRpLqBZf34ZinR8bU2_ZRAUOjKAD3+tKRFaEQHtt8Q@mail.gmail.com/ |
| In the Linux kernel, the following vulnerability has been resolved:
PCI: Fix dropping valid root bus resources with .end = zero
On r8a7791/koelsch:
kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
# cat /sys/kernel/debug/kmemleak
unreferenced object 0xc3a34e00 (size 64):
comm "swapper/0", pid 1, jiffies 4294937460 (age 199.080s)
hex dump (first 32 bytes):
b4 5d 81 f0 b4 5d 81 f0 c0 b0 a2 c3 00 00 00 00 .]...]..........
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<fe3aa979>] __kmalloc+0xf0/0x140
[<34bd6bc0>] resource_list_create_entry+0x18/0x38
[<767046bc>] pci_add_resource_offset+0x20/0x68
[<b3f3edf2>] devm_of_pci_get_host_bridge_resources.constprop.0+0xb0/0x390
When coalescing two resources for a contiguous aperture, the second
resource is enlarged to cover the full contiguous range, while the first
resource is marked invalid. This invalidation is done by clearing the
flags, start, and end members.
When adding the initial resources to the bus later, invalid resources are
skipped. Unfortunately, the check for an invalid resource considers only
the end member, causing false positives.
E.g. on r8a7791/koelsch, root bus resource 0 ("bus 00") is skipped, and no
longer registered with pci_bus_insert_busn_res() (causing the memory leak),
nor printed:
pci-rcar-gen2 ee090000.pci: host bridge /soc/pci@ee090000 ranges:
pci-rcar-gen2 ee090000.pci: MEM 0x00ee080000..0x00ee08ffff -> 0x00ee080000
pci-rcar-gen2 ee090000.pci: PCI: revision 11
pci-rcar-gen2 ee090000.pci: PCI host bridge to bus 0000:00
-pci_bus 0000:00: root bus resource [bus 00]
pci_bus 0000:00: root bus resource [mem 0xee080000-0xee08ffff]
Fix this by only skipping resources where all of the flags, start, and end
members are zero. |
| In the Linux kernel, the following vulnerability has been resolved:
posix-timers: Prevent RT livelock in itimer_delete()
itimer_delete() has a retry loop when the timer is concurrently expired. On
non-RT kernels this just spin-waits until the timer callback has completed,
except for posix CPU timers which have HAVE_POSIX_CPU_TIMERS_TASK_WORK
enabled.
In that case and on RT kernels the existing task could live lock when
preempting the task which does the timer delivery.
Replace spin_unlock() with an invocation of timer_wait_running() to handle
it the same way as the other retry loops in the posix timer code. |
| In the Linux kernel, the following vulnerability has been resolved:
block/rq_qos: protect rq_qos apis with a new lock
commit 50e34d78815e ("block: disable the elevator int del_gendisk")
move rq_qos_exit() from disk_release() to del_gendisk(), this will
introduce some problems:
1) If rq_qos_add() is triggered by enabling iocost/iolatency through
cgroupfs, then it can concurrent with del_gendisk(), it's not safe to
write 'q->rq_qos' concurrently.
2) Activate cgroup policy that is relied on rq_qos will call
rq_qos_add() and blkcg_activate_policy(), and if rq_qos_exit() is
called in the middle, null-ptr-dereference will be triggered in
blkcg_activate_policy().
3) blkg_conf_open_bdev() can call blkdev_get_no_open() first to find the
disk, then if rq_qos_exit() from del_gendisk() is done before
rq_qos_add(), then memory will be leaked.
This patch add a new disk level mutex 'rq_qos_mutex':
1) The lock will protect rq_qos_exit() directly.
2) For wbt that doesn't relied on blk-cgroup, rq_qos_add() can only be
called from disk initialization for now because wbt can't be
destructed until rq_qos_exit(), so it's safe not to protect wbt for
now. Hoever, in case that rq_qos dynamically destruction is supported
in the furture, this patch also protect rq_qos_add() from wbt_init()
directly, this is enough because blk-sysfs already synchronize
writers with disk removal.
3) For iocost and iolatency, in order to synchronize disk removal and
cgroup configuration, the lock is held after blkdev_get_no_open()
from blkg_conf_open_bdev(), and is released in blkg_conf_exit().
In order to fix the above memory leak, disk_live() is checked after
holding the new lock. |
