[PATCH] nvme: tcp: avoid race between lock and destroy of queue_lock
Shin'ichiro Kawasaki
shinichiro.kawasaki at wdc.com
Wed Sep 11 23:27:07 PDT 2024
Commit 76d54bf20cdc ("nvme-tcp: don't access released socket during
error recovery") added a mutex_lock() call for the queue->queue_lock
in nvme_tcp_get_address(). However, the mutex_lock() races with
mutex_destroy() in nvme_tcp_free_queue(), and causes the WARN below.
DEBUG_LOCKS_WARN_ON(lock->magic != lock)
WARNING: CPU: 3 PID: 34077 at kernel/locking/mutex.c:587 __mutex_lock+0xcf0/0x1220
Modules linked in: nvmet_tcp nvmet nvme_tcp nvme_fabrics iw_cm ib_cm ib_core pktcdvd nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables qrtr sunrpc ppdev 9pnet_virtio 9pnet pcspkr netfs parport_pc parport e1000 i2c_piix4 i2c_smbus loop fuse nfnetlink zram bochs drm_vram_helper drm_ttm_helper ttm drm_kms_helper xfs drm sym53c8xx floppy nvme scsi_transport_spi nvme_core nvme_auth serio_raw ata_generic pata_acpi dm_multipath qemu_fw_cfg [last unloaded: ib_uverbs]
CPU: 3 UID: 0 PID: 34077 Comm: udisksd Not tainted 6.11.0-rc7 #319
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
RIP: 0010:__mutex_lock+0xcf0/0x1220
Code: 08 84 d2 0f 85 c8 04 00 00 8b 15 ef b6 c8 01 85 d2 0f 85 78 f4 ff ff 48 c7 c6 20 93 ee af 48 c7 c7 60 91 ee af e8 f0 a7 6d fd <0f> 0b e9 5e f4 ff ff 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1
RSP: 0018:ffff88811305f760 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff88812c652058 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: ffff88811305f8b0 R08: 0000000000000001 R09: ffffed1075c36341
R10: ffff8883ae1b1a0b R11: 0000000000010498 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff88812c652058
FS: 00007f9713ae4980(0000) GS:ffff8883ae180000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcd78483c7c CR3: 0000000122c38000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
? __warn.cold+0x5b/0x1af
? __mutex_lock+0xcf0/0x1220
? report_bug+0x1ec/0x390
? handle_bug+0x3c/0x80
? exc_invalid_op+0x13/0x40
? asm_exc_invalid_op+0x16/0x20
? __mutex_lock+0xcf0/0x1220
? nvme_tcp_get_address+0xc2/0x1e0 [nvme_tcp]
? __pfx___mutex_lock+0x10/0x10
? __lock_acquire+0xd6a/0x59e0
? nvme_tcp_get_address+0xc2/0x1e0 [nvme_tcp]
nvme_tcp_get_address+0xc2/0x1e0 [nvme_tcp]
? __pfx_nvme_tcp_get_address+0x10/0x10 [nvme_tcp]
nvme_sysfs_show_address+0x81/0xc0 [nvme_core]
dev_attr_show+0x42/0x80
? __asan_memset+0x1f/0x40
sysfs_kf_seq_show+0x1f0/0x370
seq_read_iter+0x2cb/0x1130
? rw_verify_area+0x3b1/0x590
? __mutex_lock+0x433/0x1220
vfs_read+0x6a6/0xa20
? lockdep_hardirqs_on+0x78/0x100
? __pfx_vfs_read+0x10/0x10
ksys_read+0xf7/0x1d0
? __pfx_ksys_read+0x10/0x10
? __x64_sys_openat+0x105/0x1d0
do_syscall_64+0x93/0x180
? lockdep_hardirqs_on_prepare+0x16d/0x400
? do_syscall_64+0x9f/0x180
? lockdep_hardirqs_on+0x78/0x100
? do_syscall_64+0x9f/0x180
? __pfx_ksys_read+0x10/0x10
? lockdep_hardirqs_on_prepare+0x16d/0x400
? do_syscall_64+0x9f/0x180
? lockdep_hardirqs_on+0x78/0x100
? do_syscall_64+0x9f/0x180
? lockdep_hardirqs_on_prepare+0x16d/0x400
? do_syscall_64+0x9f/0x180
? lockdep_hardirqs_on+0x78/0x100
? do_syscall_64+0x9f/0x180
? lockdep_hardirqs_on_prepare+0x16d/0x400
? do_syscall_64+0x9f/0x180
? lockdep_hardirqs_on+0x78/0x100
? do_syscall_64+0x9f/0x180
? lockdep_hardirqs_on_prepare+0x16d/0x400
? do_syscall_64+0x9f/0x180
? lockdep_hardirqs_on+0x78/0x100
? do_syscall_64+0x9f/0x180
? do_syscall_64+0x9f/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f9713f55cfa
Code: 55 48 89 e5 48 83 ec 20 48 89 55 e8 48 89 75 f0 89 7d f8 e8 e8 74 f8 ff 48 8b 55 e8 48 8b 75 f0 41 89 c0 8b 7d f8 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 2e 44 89 c7 48 89 45 f8 e8 42 75 f8 ff 48 8b
RSP: 002b:00007ffd7f512e70 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000055c38f316859 RCX: 00007f9713f55cfa
RDX: 0000000000000fff RSI: 00007ffd7f512eb0 RDI: 0000000000000011
RBP: 00007ffd7f512e90 R08: 0000000000000000 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 000055c38f317148
R13: 0000000000000000 R14: 00007f96f4004f30 R15: 000055c3b6b623c0
</TASK>
The WARN is observed when the blktests test case nvme/014 is repeated
with tcp transport. It is rare, and 200 times repeat is required to
recreate in my test environment.
To avoid the WARN, serialize the two functions nvme_tcp_get_address()
and nvme_tcp_free_queue(). Add the flag NVME_TCP_Q_REFERRED and set it
when nvme_tcp_get_address() starts. Have nvme_tcp_free_queue() wait the
flag cleared so that it does not run until nvme_tcp_get_address() ends.
Also check the NVME_TCP_Q_ALLOCATED flag when nvme_tcp_get_address()
starts. This flag is cleared at the nvme_tcp_free_queue() start, then it
ensures that nvme_tcp_get_address() is not executed while
nvme_tcp_free_queue() runs.
Of note is that nvme_tcp_stop_queue() locks the queue->queue_lock in
same manner as nvme_tcp_get_address(). However, nvme_tcp_stop_queue() is
called in sequence before nvme_tcp_free_queue(), then it is safe to
assume that the queue->queue_lock is not yet destroyed at
nvme_tcp_stop_queue() call. Therefore this fix does not touch
nvme_tcp_stop_queue().
Fixes: 76d54bf20cdc ("nvme-tcp: don't access released socket during error recovery")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki at wdc.com>
---
drivers/nvme/host/tcp.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index a2a47d3ab99f..1457ffda207b 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -127,6 +127,7 @@ enum nvme_tcp_queue_flags {
NVME_TCP_Q_ALLOCATED = 0,
NVME_TCP_Q_LIVE = 1,
NVME_TCP_Q_POLLING = 2,
+ NVME_TCP_Q_REFERRED = 3,
};
enum nvme_tcp_recv_state {
@@ -1365,6 +1366,9 @@ static void nvme_tcp_free_queue(struct nvme_ctrl *nctrl, int qid)
if (!test_and_clear_bit(NVME_TCP_Q_ALLOCATED, &queue->flags))
return;
+ wait_on_bit_io(&queue->flags, NVME_TCP_Q_REFERRED,
+ TASK_UNINTERRUPTIBLE);
+
if (queue->hdr_digest || queue->data_digest)
nvme_tcp_free_crypto(queue);
@@ -2613,7 +2617,14 @@ static int nvme_tcp_get_address(struct nvme_ctrl *ctrl, char *buf, int size)
{
struct nvme_tcp_queue *queue = &to_tcp_ctrl(ctrl)->queues[0];
struct sockaddr_storage src_addr;
- int ret, len;
+ int ret, len = 0;
+
+ /* Serialize this function and nvme_tcp_free_queue() */
+ if (test_and_set_bit(NVME_TCP_Q_REFERRED, &queue->flags))
+ return 0;
+
+ if (!test_bit(NVME_TCP_Q_ALLOCATED, &queue->flags))
+ goto out;
len = nvmf_get_address(ctrl, buf, size);
@@ -2631,6 +2642,9 @@ static int nvme_tcp_get_address(struct nvme_ctrl *ctrl, char *buf, int size)
done:
mutex_unlock(&queue->queue_lock);
+out:
+ clear_and_wake_up_bit(NVME_TCP_Q_REFERRED, &queue->flags);
+
return len;
}
--
2.45.2
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