Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
RDMA/iwcm: Fix workqueue list corruption by removing work_list
The commit e1168f0 (“RDMA/iwcm: Simplify cm_event_handler()”) changed the work submission logic to unconditionally call queue_work() with the expectation that queue_work() would have no effect if work was already pending. The problem is that a free list of struct iwcm_work is used (for which struct work_struct is embedded), so each call to queue_work() is basically unique and therefore does indeed queue the work.
This causes a problem in the work handler which walks the work_list until it’s empty to process entries. This means that a single run of the work handler could process item N+1 and release it back to the free list while the actual workqueue entry is still queued. It could then get reused (INIT_WORK…) and lead to list corruption in the workqueue logic.
Fix this by just removing the work_list. The workqueue already does this for us.
This fixes the following error that was observed when stress testing with ucmatose on an Intel E830 in iWARP mode:
[ 151.465780] list_del corruption. next->prev should be ffff9f0915c69c08, but was ffff9f0a1116be08. (next=ffff9f0a15b11c08)
[ 151.466639] ————[ cut here ]————
[ 151.466986] kernel BUG at lib/list_debug.c:67!
[ 151.467349] Oops: invalid opcode: 0000 [#1] SMP NOPTI
[ 151.467753] CPU: 14 UID: 0 PID: 2306 Comm: kworker/u64:18 Not tainted 6.19.0-rc4+ #1 PREEMPT(voluntary)
[ 151.468466] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 151.469192] Workqueue: 0x0 (iw_cm_wq)
[ 151.469478] RIP: 0010:__list_del_entry_valid_or_report+0xf0/0x100
[ 151.469942] Code: c7 58 5f 4c b2 e8 10 50 aa ff 0f 0b 48 89 ef e8 36 57 cb ff 48 8b 55 08 48 89 e9 48 89 de 48 c7 c7 a8 5f 4c b2 e8 f0 4f aa ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90
[ 151.471323] RSP: 0000:ffffb15644e7bd68 EFLAGS: 00010046
[ 151.471712] RAX: 000000000000006d RBX: ffff9f0915c69c08 RCX: 0000000000000027
[ 151.472243] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9f0a37d9c600
[ 151.472768] RBP: ffff9f0a15b11c08 R08: 0000000000000000 R09: c0000000ffff7fff
[ 151.473294] R10: 0000000000000001 R11: ffffb15644e7bba8 R12: ffff9f092339ee68
[ 151.473817] R13: ffff9f0900059c28 R14: ffff9f092339ee78 R15: 0000000000000000
[ 151.474344] FS: 0000000000000000(0000) GS:ffff9f0a847b5000(0000) knlGS:0000000000000000
[ 151.474934] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 151.475362] CR2: 0000559e233a9088 CR3: 000000020296b004 CR4: 0000000000770ef0
[ 151.475895] PKRU: 55555554
[ 151.476118] Call Trace:
[ 151.476331]
Details
- Affected product:
- AlmaLinux 9.2 ESU , TuxCare 9.6 ESU
- Affected packages:
- kernel @ 5.14.0 (+1 more)
In the Linux kernel, the following vulnerability has been resolved:
RDMA/iwcm: Fix workqueue list corruption by removing work_list
The commit e1168f0 (“RDMA/iwcm: Simplify cm_event_handler()”) changed the work submission logic to unconditionally call queue_work() with the expectation that queue_work() would have no effect if work was already pending. The problem is that a free list of struct iwcm_work is used (for which struct work_struct is embedded), so each call to queue_work() is basically unique and therefore does indeed queue the work.
This causes a problem in the work handler which walks the work_list until it’s empty to process entries. This means that a single run of the work handler could process item N+1 and release it back to the free list while the actual workqueue entry is still queued. It could then get reused (INIT_WORK…) and lead to list corruption in the workqueue logic.
Fix this by just removing the work_list. The workqueue already does this for us.
This fixes the following error that was observed when stress testing with ucmatose on an Intel E830 in iWARP mode:
[ 151.465780] list_del corruption. next->prev should be ffff9f0915c69c08, but was ffff9f0a1116be08. (next=ffff9f0a15b11c08)
[ 151.466639] ————[ cut here ]————
[ 151.466986] kernel BUG at lib/list_debug.c:67!
[ 151.467349] Oops: invalid opcode: 0000 [#1] SMP NOPTI
[ 151.467753] CPU: 14 UID: 0 PID: 2306 Comm: kworker/u64:18 Not tainted 6.19.0-rc4+ #1 PREEMPT(voluntary)
[ 151.468466] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 151.469192] Workqueue: 0x0 (iw_cm_wq)
[ 151.469478] RIP: 0010:__list_del_entry_valid_or_report+0xf0/0x100
[ 151.469942] Code: c7 58 5f 4c b2 e8 10 50 aa ff 0f 0b 48 89 ef e8 36 57 cb ff 48 8b 55 08 48 89 e9 48 89 de 48 c7 c7 a8 5f 4c b2 e8 f0 4f aa ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90
[ 151.471323] RSP: 0000:ffffb15644e7bd68 EFLAGS: 00010046
[ 151.471712] RAX: 000000000000006d RBX: ffff9f0915c69c08 RCX: 0000000000000027
[ 151.472243] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9f0a37d9c600
[ 151.472768] RBP: ffff9f0a15b11c08 R08: 0000000000000000 R09: c0000000ffff7fff
[ 151.473294] R10: 0000000000000001 R11: ffffb15644e7bba8 R12: ffff9f092339ee68
[ 151.473817] R13: ffff9f0900059c28 R14: ffff9f092339ee78 R15: 0000000000000000
[ 151.474344] FS: 0000000000000000(0000) GS:ffff9f0a847b5000(0000) knlGS:0000000000000000
[ 151.474934] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 151.475362] CR2: 0000559e233a9088 CR3: 000000020296b004 CR4: 0000000000770ef0
[ 151.475895] PKRU: 55555554
[ 151.476118] Call Trace:
[ 151.476331]