Bug 2418874 (CVE-2025-40250)

Summary: CVE-2025-40250 kernel: net/mlx5: Clean up only new IRQ glue on request_irq() failure
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: ---
Doc Text:
Error handling in mlx5_irq_alloc() destroys the entire CPU affinity rmap instead of just the failed mapping when request_irq() returns an error. Concurrent threads accessing the rmap trigger a general protection fault as they dereference freed memory. The crash signature shows free_irq_cpu_rmap() accessing corrupted pointers during IRQ vector exhaustion scenarios.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2025-12-04 17:02:24 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: Clean up only new IRQ glue on request_irq() failure

The mlx5_irq_alloc() function can inadvertently free the entire rmap
and end up in a crash[1] when the other threads tries to access this,
when request_irq() fails due to exhausted IRQ vectors. This commit
modifies the cleanup to remove only the specific IRQ mapping that was
just added.

This prevents removal of other valid mappings and ensures precise
cleanup of the failed IRQ allocation's associated glue object.

Note: This error is observed when both fwctl and rds configs are enabled.

[1]
mlx5_core 0000:05:00.0: Successfully registered panic handler for port 1
mlx5_core 0000:05:00.0: mlx5_irq_alloc:293:(pid 66740): Failed to
request irq. err = -28
infiniband mlx5_0: mlx5_ib_test_wc:290:(pid 66740): Error -28 while
trying to test write-combining support
mlx5_core 0000:05:00.0: Successfully unregistered panic handler for port 1
mlx5_core 0000:06:00.0: Successfully registered panic handler for port 1
mlx5_core 0000:06:00.0: mlx5_irq_alloc:293:(pid 66740): Failed to
request irq. err = -28
infiniband mlx5_0: mlx5_ib_test_wc:290:(pid 66740): Error -28 while
trying to test write-combining support
mlx5_core 0000:06:00.0: Successfully unregistered panic handler for port 1
mlx5_core 0000:03:00.0: mlx5_irq_alloc:293:(pid 28895): Failed to
request irq. err = -28
mlx5_core 0000:05:00.0: mlx5_irq_alloc:293:(pid 28895): Failed to
request irq. err = -28
general protection fault, probably for non-canonical address
0xe277a58fde16f291: 0000 [#1] SMP NOPTI

RIP: 0010:free_irq_cpu_rmap+0x23/0x7d
Call Trace:
   <TASK>
   ? show_trace_log_lvl+0x1d6/0x2f9
   ? show_trace_log_lvl+0x1d6/0x2f9
   ? mlx5_irq_alloc.cold+0x5d/0xf3 [mlx5_core]
   ? __die_body.cold+0x8/0xa
   ? die_addr+0x39/0x53
   ? exc_general_protection+0x1c4/0x3e9
   ? dev_vprintk_emit+0x5f/0x90
   ? asm_exc_general_protection+0x22/0x27
   ? free_irq_cpu_rmap+0x23/0x7d
   mlx5_irq_alloc.cold+0x5d/0xf3 [mlx5_core]
   irq_pool_request_vector+0x7d/0x90 [mlx5_core]
   mlx5_irq_request+0x2e/0xe0 [mlx5_core]
   mlx5_irq_request_vector+0xad/0xf7 [mlx5_core]
   comp_irq_request_pci+0x64/0xf0 [mlx5_core]
   create_comp_eq+0x71/0x385 [mlx5_core]
   ? mlx5e_open_xdpsq+0x11c/0x230 [mlx5_core]
   mlx5_comp_eqn_get+0x72/0x90 [mlx5_core]
   ? xas_load+0x8/0x91
   mlx5_comp_irqn_get+0x40/0x90 [mlx5_core]
   mlx5e_open_channel+0x7d/0x3c7 [mlx5_core]
   mlx5e_open_channels+0xad/0x250 [mlx5_core]
   mlx5e_open_locked+0x3e/0x110 [mlx5_core]
   mlx5e_open+0x23/0x70 [mlx5_core]
   __dev_open+0xf1/0x1a5
   __dev_change_flags+0x1e1/0x249
   dev_change_flags+0x21/0x5c
   do_setlink+0x28b/0xcc4
   ? __nla_parse+0x22/0x3d
   ? inet6_validate_link_af+0x6b/0x108
   ? cpumask_next+0x1f/0x35
   ? __snmp6_fill_stats64.constprop.0+0x66/0x107
   ? __nla_validate_parse+0x48/0x1e6
   __rtnl_newlink+0x5ff/0xa57
   ? kmem_cache_alloc_trace+0x164/0x2ce
   rtnl_newlink+0x44/0x6e
   rtnetlink_rcv_msg+0x2bb/0x362
   ? __netlink_sendskb+0x4c/0x6c
   ? netlink_unicast+0x28f/0x2ce
   ? rtnl_calcit.isra.0+0x150/0x146
   netlink_rcv_skb+0x5f/0x112
   netlink_unicast+0x213/0x2ce
   netlink_sendmsg+0x24f/0x4d9
   __sock_sendmsg+0x65/0x6a
   ____sys_sendmsg+0x28f/0x2c9
   ? import_iovec+0x17/0x2b
   ___sys_sendmsg+0x97/0xe0
   __sys_sendmsg+0x81/0xd8
   do_syscall_64+0x35/0x87
   entry_SYSCALL_64_after_hwframe+0x6e/0x0
RIP: 0033:0x7fc328603727
Code: c3 66 90 41 54 41 89 d4 55 48 89 f5 53 89 fb 48 83 ec 10 e8 0b ed
ff ff 44 89 e2 48 89 ee 89 df 41 89 c0 b8 2e 00 00 00 0f 05 <48> 3d 00
f0 ff ff 77 35 44 89 c7 48 89 44 24 08 e8 44 ed ff ff 48
RSP: 002b:00007ffe8eb3f1a0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007fc328603727
RDX: 0000000000000000 RSI: 00007ffe8eb3f1f0 RDI: 000000000000000d
RBP: 00007ffe8eb3f1f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00000000000
---truncated---
Comment 1 Alexander B 2025-12-05 14:18:35 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025120430-CVE-2025-40250-fa72@gregkh/T