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Thu, 05 Nov 2026 09:40:35 -0800 (PST) Received: from i4-l-hqh5357-03.ad.psu.edu ([130.203.139.71]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-91ea6ac8d02sm673786d6.42.2026.11.05.09.40.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Nov 2026 09:40:33 -0800 (PST) From: Shuangpeng Bai To: Bernard Metzler , Jason Gunthorpe , Leon Romanovsky Cc: Shuangpeng Bai , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [BUG] RDMA/siw: slab-use-after-free in siw_cep_set_free Date: Thu, 5 Nov 2026 12:37:47 -0500 Message-ID: <20261105173754.660897-1-shuangpeng.kernel@gmail.com> X-Mailer: git-send-email 2.43.0 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi Kernel Maintainers, I hit the following report while testing current upstream kernel: KASAN: slab-use-after-free in _raw_spin_lock_irqsave This is a SIW CEP lifetime bug reached from `siw_cep_set_free()`'s `wake_up(&cep->waitq)`. on commit: 05441d697f7f9a927264f4058cbbc6a03dfcac9d (7.4.0-rc1) To help trigger the bug more reliably, I applied a minimal diagnostic patch that only adds delays and print statements. A related CEP lifetime concern was raised in: Link: https://lore.kernel.org/linux-rdma/05b91f98-e3a3-793a-9197-f09d84acfaf7@linux.dev/ This report provides a reproducible TX-worker race in `siw_qp_cm_drop()` around the `siw_cep_set_free()` unlock-to- `wake_up()` window. The reproducer and .config files are here. https://gist.github.com/shuangpengbai/0ef6a31bdb90f4f245b5f86b76775bc5 I am happy to test debug patches or provide additional information. Reported-by: Shuangpeng Bai ================================================================== BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave (include/linux/instrumented.h:112 include/linux/atomic/atomic-instrumented.h:1300 include/asm-generic/qspinlock.h:112 include/linux/spinlock.h:188 include/linux/spinlock_api_smp.h:156 kernel/locking/spinlock.c:181) Write of size 4 at addr ffff88810d742230 by task siw_tx/1/78 Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) kasan_report (mm/kasan/report.c:595) kasan_check_range (mm/kasan/generic.c:200) _raw_spin_lock_irqsave (include/linux/instrumented.h:112 include/linux/atomic/atomic-instrumented.h:1300 include/asm-generic/qspinlock.h:112 include/linux/spinlock.h:188 include/linux/spinlock_api_smp.h:156 kernel/locking/spinlock.c:181) __wake_up (kernel/sched/wait.c:124 kernel/sched/wait.c:146) siw_qp_cm_drop (drivers/infiniband/sw/siw/siw_cm.c:517) siw_sq_resume (drivers/infiniband/sw/siw/siw_qp_tx.c:1190) siw_run_sq (drivers/infiniband/sw/siw/siw_qp_tx.c:1278) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) Allocated by task 340 on cpu 1 at 18.058572s: kasan_save_track (mm/kasan/common.c:57 mm/kasan/common.c:78) __kasan_kmalloc (mm/kasan/common.c:409 mm/kasan/common.c:426) siw_cep_alloc (include/linux/slab.h:991 include/linux/slab.h:1312 drivers/infiniband/sw/siw/siw_cm.c:210) siw_connect (drivers/infiniband/sw/siw/siw_cm.c:1487) iw_cm_connect (drivers/infiniband/core/iwcm.c:730) rdma_connect_locked (drivers/infiniband/core/cma.c:4490 drivers/infiniband/core/cma.c:4530) rdma_connect_ece (drivers/infiniband/core/cma.c:4562 drivers/infiniband/core/cma.c:4585) ucma_connect (drivers/infiniband/core/ucma.c:1148) ucma_write (drivers/infiniband/core/ucma.c:1869) vfs_write (fs/read_write.c:685) ksys_write (fs/read_write.c:739) do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Freed by task 340 on cpu 1 at 18.111920s: kasan_save_track (mm/kasan/common.c:57 mm/kasan/common.c:78) kasan_save_free_info (mm/kasan/generic.c:584) __kasan_slab_free (mm/kasan/common.c:264 mm/kasan/common.c:296) kfree (include/linux/kasan.h:235 mm/slub.c:2780 mm/slub.c:6630 mm/slub.c:6923) siw_destroy_qp (drivers/infiniband/sw/siw/siw_verbs.c:635) ib_destroy_qp_user (drivers/infiniband/core/verbs.c:2182) uverbs_free_qp (drivers/infiniband/core/uverbs_std_types_qp.c:34) destroy_hw_idr_uobject (drivers/infiniband/core/rdma_core.c:579) uverbs_destroy_uobject (drivers/infiniband/core/rdma_core.c:172) uobj_destroy (drivers/infiniband/core/rdma_core.c:240) ib_uverbs_cmd_verbs (drivers/infiniband/core/uverbs_ioctl.c:379 drivers/infiniband/core/uverbs_ioctl.c:526) ib_uverbs_ioctl (drivers/infiniband/core/uverbs_ioctl.c:555) __se_sys_ioctl (fs/ioctl.c:51 fs/ioctl.c:597 fs/ioctl.c:583) do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) The buggy address belongs to the object at ffff88810d742200 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 48 bytes inside of freed 256-byte region [ffff88810d742200, ffff88810d742300) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10d742 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x200000000000040(head|node=0|zone=2) page_type: f5(slab) raw: 0200000000000040 ffff888100041b40 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 0200000000000040 ffff888100041b40 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 0200000000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88810d742100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88810d742180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88810d742200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88810d742280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810d742300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Best, Shuangpeng