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Shay Drory 858914d1ad net/mlx5: DR, Fix circular locking dependency in dump 
[ Upstream commit 2700b7e603 ]

Fix a circular locking dependency between dbg_mutex and the domain
rx/tx mutexes that could lead to a deadlock.

The dump path in dr_dump_domain_all() was acquiring locks in the order:
  dbg_mutex -> rx.mutex -> tx.mutex

While the table/matcher creation paths acquire locks in the order:
  rx.mutex -> tx.mutex -> dbg_mutex

This inverted lock ordering creates a circular dependency. Fix this by
changing dr_dump_domain_all() to acquire the domain lock before
dbg_mutex, matching the order used in mlx5dr_table_create() and
mlx5dr_matcher_create().

Lockdep splat:
 ======================================================
 WARNING: possible circular locking dependency detected
 6.19.0-rc6net_next_e817c4e #1 Not tainted
 ------------------------------------------------------
 sos/30721 is trying to acquire lock:
 ffff888102df5900 (&dmn->info.rx.mutex){+.+.}-{4:4}, at:
dr_dump_start+0x131/0x450 [mlx5_core]

 but task is already holding lock:
 ffff888102df5bc0 (&dmn->dump_info.dbg_mutex){+.+.}-{4:4}, at:
dr_dump_start+0x10b/0x450 [mlx5_core]

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #2 (&dmn->dump_info.dbg_mutex){+.+.}-{4:4}:
        __mutex_lock+0x91/0x1060
        mlx5dr_matcher_create+0x377/0x5e0 [mlx5_core]
        mlx5_cmd_dr_create_flow_group+0x62/0xd0 [mlx5_core]
        mlx5_create_flow_group+0x113/0x1c0 [mlx5_core]
        mlx5_chains_create_prio+0x453/0x2290 [mlx5_core]
        mlx5_chains_get_table+0x2e2/0x980 [mlx5_core]
        esw_chains_create+0x1e6/0x3b0 [mlx5_core]
        esw_create_offloads_fdb_tables.cold+0x62/0x63f [mlx5_core]
        esw_offloads_enable+0x76f/0xd20 [mlx5_core]
        mlx5_eswitch_enable_locked+0x35a/0x500 [mlx5_core]
        mlx5_devlink_eswitch_mode_set+0x561/0x950 [mlx5_core]
        devlink_nl_eswitch_set_doit+0x67/0xe0
        genl_family_rcv_msg_doit+0xe0/0x130
        genl_rcv_msg+0x188/0x290
        netlink_rcv_skb+0x4b/0xf0
        genl_rcv+0x24/0x40
        netlink_unicast+0x1ed/0x2c0
        netlink_sendmsg+0x210/0x450
        __sock_sendmsg+0x38/0x60
        __sys_sendto+0x119/0x180
        __x64_sys_sendto+0x20/0x30
        do_syscall_64+0x70/0xd00
        entry_SYSCALL_64_after_hwframe+0x4b/0x53

 -> #1 (&dmn->info.tx.mutex){+.+.}-{4:4}:
        __mutex_lock+0x91/0x1060
        mlx5dr_table_create+0x11d/0x530 [mlx5_core]
        mlx5_cmd_dr_create_flow_table+0x62/0x140 [mlx5_core]
        __mlx5_create_flow_table+0x46f/0x960 [mlx5_core]
        mlx5_create_flow_table+0x16/0x20 [mlx5_core]
        esw_create_offloads_fdb_tables+0x136/0x240 [mlx5_core]
        esw_offloads_enable+0x76f/0xd20 [mlx5_core]
        mlx5_eswitch_enable_locked+0x35a/0x500 [mlx5_core]
        mlx5_devlink_eswitch_mode_set+0x561/0x950 [mlx5_core]
        devlink_nl_eswitch_set_doit+0x67/0xe0
        genl_family_rcv_msg_doit+0xe0/0x130
        genl_rcv_msg+0x188/0x290
        netlink_rcv_skb+0x4b/0xf0
        genl_rcv+0x24/0x40
        netlink_unicast+0x1ed/0x2c0
        netlink_sendmsg+0x210/0x450
        __sock_sendmsg+0x38/0x60
        __sys_sendto+0x119/0x180
        __x64_sys_sendto+0x20/0x30
        do_syscall_64+0x70/0xd00
        entry_SYSCALL_64_after_hwframe+0x4b/0x53

 -> #0 (&dmn->info.rx.mutex){+.+.}-{4:4}:
        __lock_acquire+0x18b6/0x2eb0
        lock_acquire+0xd3/0x2c0
        __mutex_lock+0x91/0x1060
        dr_dump_start+0x131/0x450 [mlx5_core]
        seq_read_iter+0xe3/0x410
        seq_read+0xfb/0x130
        full_proxy_read+0x53/0x80
        vfs_read+0xba/0x330
        ksys_read+0x65/0xe0
        do_syscall_64+0x70/0xd00
        entry_SYSCALL_64_after_hwframe+0x4b/0x53

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&dmn->dump_info.dbg_mutex);
                                lock(&dmn->info.tx.mutex);
                                lock(&dmn->dump_info.dbg_mutex);
   lock(&dmn->info.rx.mutex);

                   *** DEADLOCK ***

Fixes: 9222f0b27d ("net/mlx5: DR, Add support for dumping steering info")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Alex Vesker <valex@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260224114652.1787431-2-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2026-03-04 07:20:51 -05:00
arch arm64: hugetlbpage: avoid unused-but-set-parameter warning (gcc-16) 2026-03-04 07:20:42 -05:00
block block: decouple secure erase size limit from discard size limit 2026-03-04 07:19:38 -05:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: authencesn - reject too-short AAD (assoclen<8) to match ESP/ESN spec 2026-01-30 10:32:12 +01:00
Documentation ipv6: Move ipv6_fl_list from ipv6_pinfo to inet_sock. 2026-03-04 07:20:44 -05:00
drivers net/mlx5: DR, Fix circular locking dependency in dump 2026-03-04 07:20:51 -05:00
fs erofs: fix interlaced plain identification for encoded extents 2026-03-04 07:20:50 -05:00
include net: add a common function to compute features for upper devices 2026-03-04 07:20:50 -05:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/timeout: annotate data race in io_flush_timeouts() 2026-03-04 07:19:36 -05:00
ipc ipc: don't audit capability check in ipc_permissions() 2026-02-26 14:59:19 -08:00
kernel Remove WARN_ALL_UNSEEDED_RANDOM kernel config option 2026-03-04 07:20:46 -05:00
lib Remove WARN_ALL_UNSEEDED_RANDOM kernel config option 2026-03-04 07:20:46 -05:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm mm/slab: fix false lockdep warning in __kfree_rcu_sheaf() 2026-02-26 14:59:14 -08:00
net net: add a common function to compute features for upper devices 2026-03-04 07:20:50 -05:00
rust rust: cpufreq: always inline functions using build_assert with arguments 2026-03-04 07:19:37 -05:00
samples samples/ftrace: Adjust LoongArch register restore order in direct calls 2026-01-08 10:17:11 +01:00
scripts modpost: Amend ppc64 save/restfpr symnames for -Os build 2026-03-04 07:20:07 -05:00
security apparmor: fix aa_label to return state from compount and component match 2026-02-26 14:59:42 -08:00
sound ALSA: hda/hdmi: Add quirk for TUXEDO IBS14G6 2026-03-04 07:20:42 -05:00
tools rtla: Fix NULL pointer dereference in actions_parse 2026-03-04 07:20:13 -05:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM: Don't clobber irqfd routing type when deassigning irqfd 2026-02-11 13:41:44 +01:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +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 MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap 8 hotfixes. 4 are cc:stable, 7 are against mm/. 2025-11-26 12:38:05 -08:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.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: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS soc: fixes for 6.18, part 4 2025-11-28 09:57:31 -08:00
Makefile Linux 6.18.15 2026-02-27 16:05:10 -05:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.