| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-21886: RDMA/mlx5: Fix implicit ODP hang on parent deregistration |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| RDMA/mlx5: Fix implicit ODP hang on parent deregistration |
| |
| Fix the destroy_unused_implicit_child_mr() to prevent hanging during |
| parent deregistration as of below [1]. |
| |
| Upon entering destroy_unused_implicit_child_mr(), the reference count |
| for the implicit MR parent is incremented using: |
| refcount_inc_not_zero(). |
| |
| A corresponding decrement must be performed if |
| free_implicit_child_mr_work() is not called. |
| |
| The code has been updated to properly manage the reference count that |
| was incremented. |
| |
| [1] |
| INFO: task python3:2157 blocked for more than 120 seconds. |
| Not tainted 6.12.0-rc7+ #1633 |
| "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. |
| task:python3 state:D stack:0 pid:2157 tgid:2157 ppid:1685 flags:0x00000000 |
| Call Trace: |
| <TASK> |
| __schedule+0x420/0xd30 |
| schedule+0x47/0x130 |
| __mlx5_ib_dereg_mr+0x379/0x5d0 [mlx5_ib] |
| ? __pfx_autoremove_wake_function+0x10/0x10 |
| 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+0xc1/0x2f0 |
| ? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs] |
| ? ib_uverbs_ioctl+0x116/0x170 [ib_uverbs] |
| ? lock_release+0xc6/0x280 |
| ib_uverbs_ioctl+0xe7/0x170 [ib_uverbs] |
| ? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs] |
| __x64_sys_ioctl+0x1b0/0xa70 |
| ? kmem_cache_free+0x221/0x400 |
| do_syscall_64+0x6b/0x140 |
| entry_SYSCALL_64_after_hwframe+0x76/0x7e |
| RIP: 0033:0x7f20f21f017b |
| RSP: 002b:00007ffcfc4a77c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 |
| RAX: ffffffffffffffda RBX: 00007ffcfc4a78d8 RCX: 00007f20f21f017b |
| RDX: 00007ffcfc4a78c0 RSI: 00000000c0181b01 RDI: 0000000000000003 |
| RBP: 00007ffcfc4a78a0 R08: 000056147d125190 R09: 00007f20f1f14c60 |
| R10: 0000000000000001 R11: 0000000000000246 R12: 00007ffcfc4a7890 |
| R13: 000000000000001c R14: 000056147d100fc0 R15: 00007f20e365c9d0 |
| </TASK> |
| |
| The Linux kernel CVE team has assigned CVE-2025-21886 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.12.13 with commit 7cc8f681f6d4ae4478ae0f60485fc768f2b450da and fixed in 6.12.18 with commit cb96ae783e7249e8e5a50c22952c0bb2983133df |
| Issue introduced in 6.13.2 with commit edfb65dbb9ffd3102f3ff4dd21316158e56f1976 and fixed in 6.13.6 with commit a095ede2daca49d15e74d66d014883f2fa8bb924 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2025-21886 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/infiniband/hw/mlx5/odp.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/cb96ae783e7249e8e5a50c22952c0bb2983133df |
| https://git.kernel.org/stable/c/a095ede2daca49d15e74d66d014883f2fa8bb924 |
| https://git.kernel.org/stable/c/3d8c6f26893d55fab218ad086719de1fc9bb86ba |
