Hi all, When I run the testcase liburing/accept-reust.t with CONFIG_KASAN=y and CONFIG_KASAN_EXTRA_INFO=y, I got a error reported by KASAN: Unable to handle kernel paging request at virtual address 00000c6455008008 Mem abort info: ESR = 0x0000000096000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault Data abort info: ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 user pgtable: 4k pages, 48-bit VAs, pgdp=00000001104c5000 [00000c6455008008] pgd=0000000000000000, p4d=0000000000000000 Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP Modules linked in: CPU: 6 UID: 0 PID: 352 Comm: kworker/u128:5 Not tainted 6.13.0-rc6-g0a2cb793507d #5 Hardware name: linux,dummy-virt (DT) Workqueue: iou_exit io_ring_exit_work pstate: 10000005 (nzcV daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __kasan_mempool_unpoison_object+0x38/0x170 lr : io_netmsg_cache_free+0x8c/0x180 sp : ffff800083297a90 x29: ffff800083297a90 x28: ffffd4d7f67e88e4 x27: 0000000000000003 x26: 1fffe5958011502e x25: ffff2cabff976c18 x24: 1fffe5957ff2ed83 x23: ffff2cabff976c10 x22: 00000c6455008000 x21: 0002992540200001 x20: 0000000000000000 x19: 00000c6455008000 x18: 00000000489683f8 x17: ffffd4d7f68006ac x16: ffffd4d7f67eb3e0 x15: ffffd4d7f67e88e4 x14: ffffd4d7f766deac x13: ffffd4d7f6619030 x12: ffff7a9b012e3e26 x11: 1ffffa9b012e3e25 x10: ffff7a9b012e3e25 x9 : ffffd4d7f766debc x8 : ffffd4d80971f128 x7 : 0000000000000001 x6 : 00008564fed1c1db x5 : ffffd4d80971f128 x4 : ffff7a9b012e3e26 x3 : ffff2cabff976c00 x2 : ffffc1ffc0000000 x1 : 0000000000000000 x0 : 0002992540200001 Call trace: __kasan_mempool_unpoison_object+0x38/0x170 (P) io_netmsg_cache_free+0x8c/0x180 io_ring_exit_work+0xd4c/0x13a0 process_one_work+0x52c/0x1000 worker_thread+0x830/0xdc0 kthread+0x2bc/0x348 ret_from_fork+0x10/0x20 Code: aa0003f5 aa0103f4 8b131853 aa1303f6 (f9400662) ---[ end trace 0000000000000000 ]--- I preliminary analyzed the accept and connect code logic. In the accept-reuse.t testcase, kmsg->free_iov is not used, so when calling io_netmsg_cache_free(), the kasan_mempool_unpoison_object(kmsg->free_iov...) path should not be executed. I used the hardware watchpoint to capture the first scene of modifying kmsg->free_iov: Thread 3 hit Hardware watchpoint 7: *0xffff0000ebfc5410 Old value = 0 New value = -211812350 kasan_set_track (stack=<optimized out>, track=<optimized out>) at ./arch/arm64/include/asm/current.h:21 21 return (struct task_struct *)sp_el0; # bt kasan_set_track kasan_save_track kasan_save_free_info poison_slab_object __kasan_mempool_poison_object kasan_mempool_poison_object io_alloc_cache_put io_netmsg_recycle io_req_msg_cleanup io_connect io_issue_sqe io_queue_sqe io_req_task_submit ... It's a bit strange. It was modified by KASAN. I can't understand this. Maybe I missed something? Please let me know. Thanks. --- Li Zetao
