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Yishai Hadas 3e3bf25599 RDMA/mlx5: Fix the recovery flow of the UMR QP
[ Upstream commit d97505baea ]

This patch addresses an issue in the recovery flow of the UMR QP,
ensuring tasks do not get stuck, as highlighted by the call trace [1].

During recovery, before transitioning the QP to the RESET state, the
software must wait for all outstanding WRs to complete.

Failing to do so can cause the firmware to skip sending some flushed
CQEs with errors and simply discard them upon the RESET, as per the IB
specification.

This race condition can result in lost CQEs and tasks becoming stuck.

To resolve this, the patch sends a final WR which serves only as a
barrier before moving the QP state to RESET.

Once a CQE is received for that final WR, it guarantees that no
outstanding WRs remain, making it safe to transition the QP to RESET and
subsequently back to RTS, restoring proper functionality.

Note:
For the barrier WR, we simply reuse the failed and ready WR.
Since the QP is in an error state, it will only receive
IB_WC_WR_FLUSH_ERR. However, as it serves only as a barrier we don't
care about its status.

[1]
INFO: task rdma_resource_l:1922 blocked for more than 120 seconds.
Tainted: G        W          6.12.0-rc7+ #1626
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:rdma_resource_l state:D stack:0  pid:1922 tgid:1922  ppid:1369
     flags:0x00004004
Call Trace:
<TASK>
__schedule+0x420/0xd30
schedule+0x47/0x130
schedule_timeout+0x280/0x300
? mark_held_locks+0x48/0x80
? lockdep_hardirqs_on_prepare+0xe5/0x1a0
wait_for_completion+0x75/0x130
mlx5r_umr_post_send_wait+0x3c2/0x5b0 [mlx5_ib]
? __pfx_mlx5r_umr_done+0x10/0x10 [mlx5_ib]
mlx5r_umr_revoke_mr+0x93/0xc0 [mlx5_ib]
__mlx5_ib_dereg_mr+0x299/0x520 [mlx5_ib]
? _raw_spin_unlock_irq+0x24/0x40
? wait_for_completion+0xfe/0x130
? rdma_restrack_put+0x63/0xe0 [ib_core]
ib_dereg_mr_user+0x5f/0x120 [ib_core]
? lock_release+0xc6/0x280
destroy_hw_idr_uobject+0x1d/0x60 [ib_uverbs]
uverbs_destroy_uobject+0x58/0x1d0 [ib_uverbs]
uobj_destroy+0x3f/0x70 [ib_uverbs]
ib_uverbs_cmd_verbs+0x3e4/0xbb0 [ib_uverbs]
? __pfx_uverbs_destroy_def_handler+0x10/0x10 [ib_uverbs]
? __lock_acquire+0x64e/0x2080
? mark_held_locks+0x48/0x80
? find_held_lock+0x2d/0xa0
? lock_acquire+0xc1/0x2f0
? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs]
? __fget_files+0xc3/0x1b0
ib_uverbs_ioctl+0xe7/0x170 [ib_uverbs]
? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs]
__x64_sys_ioctl+0x1b0/0xa70
do_syscall_64+0x6b/0x140
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f99c918b17b
RSP: 002b:00007ffc766d0468 EFLAGS: 00000246 ORIG_RAX:
     0000000000000010
RAX: ffffffffffffffda RBX: 00007ffc766d0578 RCX:
     00007f99c918b17b
RDX: 00007ffc766d0560 RSI: 00000000c0181b01 RDI:
     0000000000000003
RBP: 00007ffc766d0540 R08: 00007f99c8f99010 R09:
     000000000000bd7e
R10: 00007f99c94c1c70 R11: 0000000000000246 R12:
     00007ffc766d0530
R13: 000000000000001c R14: 0000000040246a80 R15:
     0000000000000000
</TASK>

Fixes: 158e71bb69 ("RDMA/mlx5: Add a umr recovery flow")
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Reviewed-by: Michael Guralnik <michaelgur@nvidia.com>
Link: https://patch.msgid.link/27b51b92ec42dfb09d8096fcbd51878f397ce6ec.1737290141.git.leon@kernel.org
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-03-07 18:25:24 +01:00
arch arm64: dts: rockchip: change eth phy mode to rgmii-id for orangepi r1 plus lts 2025-02-27 04:30:24 -08:00
block partitions: mac: fix handling of bogus partition table 2025-02-21 14:01:36 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: api - Fix boot-up self-test race 2025-02-08 09:57:28 +01:00
Documentation strparser: Add read_sock callback 2025-02-27 04:30:19 -08:00
drivers RDMA/mlx5: Fix the recovery flow of the UMR QP 2025-03-07 18:25:24 +01:00
fs smb: client: Add check for next_buffer in receive_encrypted_standard() 2025-02-27 04:30:23 -08:00
include bpf: Fix wrong copied_seq calculation 2025-02-27 04:30:19 -08:00
init Compiler Attributes: disable __counted_by for clang < 19.1.3 2024-12-05 14:02:45 +01:00
io_uring io_uring: prevent opcode speculation 2025-02-27 04:30:21 -08:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel sched_ext: Fix incorrect assumption about migration disabled tasks in task_can_run_on_remote_rq() 2025-02-27 04:30:24 -08:00
lib lib/iov_iter: fix import_iovec_ubuf iovec management 2025-02-27 04:30:22 -08:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm,madvise,hugetlb: check for 0-length range after end address adjustment 2025-02-27 04:30:23 -08:00
net drop_monitor: fix incorrect initialization order 2025-02-27 04:30:21 -08:00
rust rust: kbuild: add -fzero-init-padding-bits to bindgen_skip_cflags 2025-02-21 14:01:39 +01:00
samples samples/landlock: Fix possible NULL dereference in parse_path() 2025-02-08 09:57:11 +01:00
scripts kbuild: Use -fzero-init-padding-bits=all 2025-02-21 14:01:27 +01:00
security KEYS: trusted: dcp: fix improper sg use with CONFIG_VMAP_STACK=y 2025-02-17 10:05:09 +01:00
sound ASoC: SOF: pcm: Clear the susbstream pointer to NULL on close 2025-02-27 04:30:23 -08:00
tools selftests/mm: build with -O2 2025-02-27 04:30:24 -08:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM: x86: switch hugepage recovery thread to vhost_task 2024-12-05 14:02:43 +01:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Kbuild updates for v6.12 2024-09-24 13:02:06 -07:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: update location of media main tree 2024-12-05 14:02:42 +01:00
Makefile Linux 6.12.17 2025-02-27 04:30:24 -08:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
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