mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-09 06:28:18 -04:00
eb41a264a3
There's a race between disabling DIM and NAPI callbacks using the dim
pointer on the RQ or SQ.
If NAPI checks the DIM state bit and sees it still set, it assumes
`rq->dim` or `sq->dim` is valid. But if DIM gets disabled right after
that check, the pointer might already be set to NULL, leading to a NULL
pointer dereference in net_dim().
Fix this by calling `synchronize_net()` before freeing the DIM context.
This ensures all in-progress NAPI callbacks are finished before the
pointer is cleared.
Kernel log:
BUG: kernel NULL pointer dereference, address: 0000000000000000
...
RIP: 0010:net_dim+0x23/0x190
...
Call Trace:
<TASK>
? __die+0x20/0x60
? page_fault_oops+0x150/0x3e0
? common_interrupt+0xf/0xa0
? sysvec_call_function_single+0xb/0x90
? exc_page_fault+0x74/0x130
? asm_exc_page_fault+0x22/0x30
? net_dim+0x23/0x190
? mlx5e_poll_ico_cq+0x41/0x6f0 [mlx5_core]
? sysvec_apic_timer_interrupt+0xb/0x90
mlx5e_handle_rx_dim+0x92/0xd0 [mlx5_core]
mlx5e_napi_poll+0x2cd/0xac0 [mlx5_core]
? mlx5e_poll_ico_cq+0xe5/0x6f0 [mlx5_core]
busy_poll_stop+0xa2/0x200
? mlx5e_napi_poll+0x1d9/0xac0 [mlx5_core]
? mlx5e_trigger_irq+0x130/0x130 [mlx5_core]
__napi_busy_loop+0x345/0x3b0
? sysvec_call_function_single+0xb/0x90
? asm_sysvec_call_function_single+0x16/0x20
? sysvec_apic_timer_interrupt+0xb/0x90
? pcpu_free_area+0x1e4/0x2e0
napi_busy_loop+0x11/0x20
xsk_recvmsg+0x10c/0x130
sock_recvmsg+0x44/0x70
__sys_recvfrom+0xbc/0x130
? __schedule+0x398/0x890
__x64_sys_recvfrom+0x20/0x30
do_syscall_64+0x4c/0x100
entry_SYSCALL_64_after_hwframe+0x4b/0x53
...
---[ end trace 0000000000000000 ]---
...
---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
Fixes: 445a25f6e1 ("net/mlx5e: Support updating coalescing configuration without resetting channels")
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/1752155624-24095-3-git-send-email-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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.