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Xiaolei Wang 64b6cd5f7b net: macb: Relocate mog_init_rings() callback from macb_mac_link_up() to macb_open() 
commit 99537d5c47 upstream.

In the non-RT kernel, local_bh_disable() merely disables preemption,
whereas it maps to an actual spin lock in the RT kernel. Consequently,
when attempting to refill RX buffers via netdev_alloc_skb() in
macb_mac_link_up(), a deadlock scenario arises as follows:

   WARNING: possible circular locking dependency detected
   6.18.0-08691-g2061f18ad76e #39 Not tainted
   ------------------------------------------------------
   kworker/0:0/8 is trying to acquire lock:
   ffff00080369bbe0 (&bp->lock){+.+.}-{3:3}, at: macb_start_xmit+0x808/0xb7c

   but task is already holding lock:
   ffff000803698e58 (&queue->tx_ptr_lock){+...}-{3:3}, at: macb_start_xmit
   +0x148/0xb7c

   which lock already depends on the new lock.

   the existing dependency chain (in reverse order) is:

   -> #3 (&queue->tx_ptr_lock){+...}-{3:3}:
          rt_spin_lock+0x50/0x1f0
          macb_start_xmit+0x148/0xb7c
          dev_hard_start_xmit+0x94/0x284
          sch_direct_xmit+0x8c/0x37c
          __dev_queue_xmit+0x708/0x1120
          neigh_resolve_output+0x148/0x28c
          ip6_finish_output2+0x2c0/0xb2c
          __ip6_finish_output+0x114/0x308
          ip6_output+0xc4/0x4a4
          mld_sendpack+0x220/0x68c
          mld_ifc_work+0x2a8/0x4f4
          process_one_work+0x20c/0x5f8
          worker_thread+0x1b0/0x35c
          kthread+0x144/0x200
          ret_from_fork+0x10/0x20

   -> #2 (_xmit_ETHER#2){+...}-{3:3}:
          rt_spin_lock+0x50/0x1f0
          sch_direct_xmit+0x11c/0x37c
          __dev_queue_xmit+0x708/0x1120
          neigh_resolve_output+0x148/0x28c
          ip6_finish_output2+0x2c0/0xb2c
          __ip6_finish_output+0x114/0x308
          ip6_output+0xc4/0x4a4
          mld_sendpack+0x220/0x68c
          mld_ifc_work+0x2a8/0x4f4
          process_one_work+0x20c/0x5f8
          worker_thread+0x1b0/0x35c
          kthread+0x144/0x200
          ret_from_fork+0x10/0x20

   -> #1 ((softirq_ctrl.lock)){+.+.}-{3:3}:
          lock_release+0x250/0x348
          __local_bh_enable_ip+0x7c/0x240
          __netdev_alloc_skb+0x1b4/0x1d8
          gem_rx_refill+0xdc/0x240
          gem_init_rings+0xb4/0x108
          macb_mac_link_up+0x9c/0x2b4
          phylink_resolve+0x170/0x614
          process_one_work+0x20c/0x5f8
          worker_thread+0x1b0/0x35c
          kthread+0x144/0x200
          ret_from_fork+0x10/0x20

   -> #0 (&bp->lock){+.+.}-{3:3}:
          __lock_acquire+0x15a8/0x2084
          lock_acquire+0x1cc/0x350
          rt_spin_lock+0x50/0x1f0
          macb_start_xmit+0x808/0xb7c
          dev_hard_start_xmit+0x94/0x284
          sch_direct_xmit+0x8c/0x37c
          __dev_queue_xmit+0x708/0x1120
          neigh_resolve_output+0x148/0x28c
          ip6_finish_output2+0x2c0/0xb2c
          __ip6_finish_output+0x114/0x308
          ip6_output+0xc4/0x4a4
          mld_sendpack+0x220/0x68c
          mld_ifc_work+0x2a8/0x4f4
          process_one_work+0x20c/0x5f8
          worker_thread+0x1b0/0x35c
          kthread+0x144/0x200
          ret_from_fork+0x10/0x20

   other info that might help us debug this:

   Chain exists of:
     &bp->lock --> _xmit_ETHER#2 --> &queue->tx_ptr_lock

    Possible unsafe locking scenario:

          CPU0                    CPU1
          ----                    ----
     lock(&queue->tx_ptr_lock);
                                  lock(_xmit_ETHER#2);
                                  lock(&queue->tx_ptr_lock);
     lock(&bp->lock);

    *** DEADLOCK ***

   Call trace:
    show_stack+0x18/0x24 (C)
    dump_stack_lvl+0xa0/0xf0
    dump_stack+0x18/0x24
    print_circular_bug+0x28c/0x370
    check_noncircular+0x198/0x1ac
    __lock_acquire+0x15a8/0x2084
    lock_acquire+0x1cc/0x350
    rt_spin_lock+0x50/0x1f0
    macb_start_xmit+0x808/0xb7c
    dev_hard_start_xmit+0x94/0x284
    sch_direct_xmit+0x8c/0x37c
    __dev_queue_xmit+0x708/0x1120
    neigh_resolve_output+0x148/0x28c
    ip6_finish_output2+0x2c0/0xb2c
    __ip6_finish_output+0x114/0x308
    ip6_output+0xc4/0x4a4
    mld_sendpack+0x220/0x68c
    mld_ifc_work+0x2a8/0x4f4
    process_one_work+0x20c/0x5f8
    worker_thread+0x1b0/0x35c
    kthread+0x144/0x200
    ret_from_fork+0x10/0x20

Notably, invoking the mog_init_rings() callback upon link establishment
is unnecessary. Instead, we can exclusively call mog_init_rings() within
the ndo_open() callback. This adjustment resolves the deadlock issue.
Furthermore, since MACB_CAPS_MACB_IS_EMAC cases do not use mog_init_rings()
when opening the network interface via at91ether_open(), moving
mog_init_rings() to macb_open() also eliminates the MACB_CAPS_MACB_IS_EMAC
check.

Fixes: 633e98a711 ("net: macb: use resolved link config in mac_link_up()")
Cc: stable@vger.kernel.org
Suggested-by: Kevin Hao <kexin.hao@windriver.com>
Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>
Link: https://patch.msgid.link/20251222015624.1994551-1-xiaolei.wang@windriver.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2026-01-08 10:17:14 +01:00
arch LoongArch: BPF: Adjust the jump offset of tail calls 2026-01-08 10:17:13 +01:00
block block: Clear BLK_ZONE_WPLUG_PLUGGED when aborting plugged BIOs 2026-01-08 10:16:58 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: seqiv - Do not use req->iv after crypto_aead_encrypt 2026-01-08 10:16:43 +01:00
Documentation dt-bindings: PCI: qcom,pcie-sm8550: Add missing required power-domains and resets 2026-01-02 12:57:27 +01:00
drivers net: macb: Relocate mog_init_rings() callback from macb_mac_link_up() to macb_open() 2026-01-08 10:17:14 +01:00
fs nfsd: Drop the client reference in client_states_open() 2026-01-08 10:17:13 +01:00
include mm: consider non-anon swap cache folios in folio_expected_ref_count() 2026-01-08 10:17:11 +01:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/rsrc: fix lost entries after cloned range 2026-01-02 12:57:30 +01:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel kernel/kexec: fix IMA when allocation happens in CMA area 2026-01-08 10:17:10 +01:00
lib idr: fix idr_alloc() returning an ID out of range 2026-01-08 10:17:10 +01:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm mm/page_owner: fix memory leak in page_owner_stack_fops->release() 2026-01-08 10:17:10 +01:00
net net: nfc: fix deadlock between nfc_unregister_device and rfkill_fop_write 2026-01-08 10:17:14 +01:00
rust rust: maple_tree: rcu_read_lock() in destructor to silence lockdep 2026-01-08 10:17:11 +01:00
samples samples/ftrace: Adjust LoongArch register restore order in direct calls 2026-01-08 10:17:11 +01:00
scripts mcb: Add missing modpost build support 2026-01-08 10:16:47 +01:00
security kernel/kexec: change the prototype of kimage_map_segment() 2026-01-08 10:17:10 +01:00
sound ASoC: qcom: qdsp6: q6asm-dai: set 10 ms period and buffer alignment. 2026-01-08 10:16:54 +01:00
tools selftests/mm: fix thread state check in uffd-unit-tests 2026-01-08 10:17:11 +01:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM: Fix last_boosted_vcpu index assignment bug 2026-01-02 12:57:21 +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 6.18.3 2026-01-02 12:57:31 +01:00
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.