On 4/30/21 3:21 PM, Palash Oswal wrote: > On Thursday, March 18, 2021 at 9:40:21 PM UTC+5:30 syzbot wrote: >> >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: 0d7588ab riscv: process: Fix no prototype for arch_dup_tas.. >> git tree: git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git fixes >> console output: https://syzkaller.appspot.com/x/log.txt?x=12dde5aed00000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=81c0b708b31626cc >> dashboard link: https://syzkaller.appspot.com/bug?extid=11bf59db879676f59e52 >> userspace arch: riscv64 >> CC: [asml.s...@xxxxxxxxx ax...@xxxxxxxxx io-u...@xxxxxxxxxxxxxxx linux-...@xxxxxxxxxxxxxxx] >> >> Unfortunately, I don't have any reproducer for this issue yet. >> >> IMPORTANT: if you fix the issue, please add the following tag to the commit: >> Reported-by: syzbot+11bf59...@xxxxxxxxxxxxxxxxxxxxxxxxx >> >> INFO: task iou-sqp-4867:4871 blocked for more than 430 seconds. >> Not tainted 5.12.0-rc2-syzkaller-00467-g0d7588ab9ef9 #0 >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> task:iou-sqp-4867 state:D stack: 0 pid: 4871 ppid: 4259 flags:0x00000004 >> Call Trace: >> [<ffffffe003bc3252>] context_switch kernel/sched/core.c:4324 [inline] >> [<ffffffe003bc3252>] __schedule+0x478/0xdec kernel/sched/core.c:5075 >> [<ffffffe003bc3c2a>] schedule+0x64/0x166 kernel/sched/core.c:5154 >> [<ffffffe0004b80ee>] io_uring_cancel_sqpoll+0x1de/0x294 fs/io_uring.c:8858 >> [<ffffffe0004c19cc>] io_sq_thread+0x548/0xe58 fs/io_uring.c:6750 >> [<ffffffe000005570>] ret_from_exception+0x0/0x14 The test might be very useful. Would you send a patch to liburing? Or mind the repro being taken as a test? >> >> Showing all locks held in the system: >> 3 locks held by kworker/u4:0/7: >> 3 locks held by kworker/1:0/19: >> 1 lock held by khungtaskd/1556: >> #0: ffffffe00592b5e8 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x32/0x1fa kernel/locking/lockdep.c:6329 >> 1 lock held by klogd/3947: >> 2 locks held by getty/4142: >> #0: ffffffe00f1aa098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x48 drivers/tty/tty_ldsem.c:340 >> #1: ffffffd010b6f2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x9ac/0xb08 drivers/tty/n_tty.c:2178 >> 2 locks held by kworker/0:1/4375: >> >> ============================================= >> >> >> >> --- >> This report is generated by a bot. It may contain errors. >> See https://goo.gl/tpsmEJ for more information about syzbot. >> syzbot engineers can be reached at syzk...@xxxxxxxxxxxxxxxx. >> >> syzbot will keep track of this issue. See: >> https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > Attaching a C reproducer for this bug: > > #define _GNU_SOURCE > > #include <fcntl.h> > #include <signal.h> > #include <stdint.h> > #include <stdlib.h> > #include <string.h> > #include <sys/mman.h> > #include <sys/syscall.h> > #include <sys/wait.h> > #include <time.h> > #include <unistd.h> > > static uint64_t current_time_ms(void) > { > struct timespec ts; > if (clock_gettime(CLOCK_MONOTONIC, &ts)) > exit(1); > return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000; > } > > #define SIZEOF_IO_URING_SQE 64 > #define SIZEOF_IO_URING_CQE 16 > #define SQ_TAIL_OFFSET 64 > #define SQ_RING_MASK_OFFSET 256 > #define SQ_RING_ENTRIES_OFFSET 264 > #define CQ_RING_ENTRIES_OFFSET 268 > #define CQ_CQES_OFFSET 320 > > struct io_sqring_offsets { > uint32_t head; > uint32_t tail; > uint32_t ring_mask; > uint32_t ring_entries; > uint32_t flags; > uint32_t dropped; > uint32_t array; > uint32_t resv1; > uint64_t resv2; > }; > > struct io_cqring_offsets { > uint32_t head; > uint32_t tail; > uint32_t ring_mask; > uint32_t ring_entries; > uint32_t overflow; > uint32_t cqes; > uint64_t resv[2]; > }; > > struct io_uring_params { > uint32_t sq_entries; > uint32_t cq_entries; > uint32_t flags; > uint32_t sq_thread_cpu; > uint32_t sq_thread_idle; > uint32_t features; > uint32_t resv[4]; > struct io_sqring_offsets sq_off; > struct io_cqring_offsets cq_off; > }; > > #define IORING_OFF_SQ_RING 0 > #define IORING_OFF_SQES 0x10000000ULL > > #define sys_io_uring_setup 425 > static long syz_io_uring_setup(volatile long a0, volatile long a1, > volatile long a2, volatile long a3, volatile long a4, volatile long > a5) > { > uint32_t entries = (uint32_t)a0; > struct io_uring_params* setup_params = (struct io_uring_params*)a1; > void* vma1 = (void*)a2; > void* vma2 = (void*)a3; > void** ring_ptr_out = (void**)a4; > void** sqes_ptr_out = (void**)a5; > uint32_t fd_io_uring = syscall(sys_io_uring_setup, entries, setup_params); > uint32_t sq_ring_sz = setup_params->sq_off.array + > setup_params->sq_entries * sizeof(uint32_t); > uint32_t cq_ring_sz = setup_params->cq_off.cqes + > setup_params->cq_entries * SIZEOF_IO_URING_CQE; > uint32_t ring_sz = sq_ring_sz > cq_ring_sz ? sq_ring_sz : cq_ring_sz; > *ring_ptr_out = mmap(vma1, ring_sz, PROT_READ | PROT_WRITE, > MAP_SHARED | MAP_POPULATE | MAP_FIXED, fd_io_uring, > IORING_OFF_SQ_RING); > uint32_t sqes_sz = setup_params->sq_entries * SIZEOF_IO_URING_SQE; > *sqes_ptr_out = mmap(vma2, sqes_sz, PROT_READ | PROT_WRITE, > MAP_SHARED | MAP_POPULATE | MAP_FIXED, fd_io_uring, IORING_OFF_SQES); > return fd_io_uring; > } > > static long syz_io_uring_submit(volatile long a0, volatile long a1, > volatile long a2, volatile long a3) > { > char* ring_ptr = (char*)a0; > char* sqes_ptr = (char*)a1; > char* sqe = (char*)a2; > uint32_t sqes_index = (uint32_t)a3; > uint32_t sq_ring_entries = *(uint32_t*)(ring_ptr + SQ_RING_ENTRIES_OFFSET); > uint32_t cq_ring_entries = *(uint32_t*)(ring_ptr + CQ_RING_ENTRIES_OFFSET); > uint32_t sq_array_off = (CQ_CQES_OFFSET + cq_ring_entries * > SIZEOF_IO_URING_CQE + 63) & ~63; > if (sq_ring_entries) > sqes_index %= sq_ring_entries; > char* sqe_dest = sqes_ptr + sqes_index * SIZEOF_IO_URING_SQE; > memcpy(sqe_dest, sqe, SIZEOF_IO_URING_SQE); > uint32_t sq_ring_mask = *(uint32_t*)(ring_ptr + SQ_RING_MASK_OFFSET); > uint32_t* sq_tail_ptr = (uint32_t*)(ring_ptr + SQ_TAIL_OFFSET); > uint32_t sq_tail = *sq_tail_ptr & sq_ring_mask; > uint32_t sq_tail_next = *sq_tail_ptr + 1; > uint32_t* sq_array = (uint32_t*)(ring_ptr + sq_array_off); > *(sq_array + sq_tail) = sqes_index; > __atomic_store_n(sq_tail_ptr, sq_tail_next, __ATOMIC_RELEASE); > return 0; > } > > static void kill_and_wait(int pid, int* status) > { > kill(-pid, SIGKILL); > kill(pid, SIGKILL); > while (waitpid(-1, status, __WALL) != pid) { > } > } > > #define WAIT_FLAGS __WALL > > uint64_t r[3] = {0xffffffffffffffff, 0x0, 0x0}; > > void trigger_bug(void) > { > intptr_t res = 0; > *(uint32_t*)0x20000204 = 0; > *(uint32_t*)0x20000208 = 2; > *(uint32_t*)0x2000020c = 0; > *(uint32_t*)0x20000210 = 0; > *(uint32_t*)0x20000218 = -1; > memset((void*)0x2000021c, 0, 12); > res = -1; > res = syz_io_uring_setup(0x7987, 0x20000200, 0x20400000, > 0x20ffd000, 0x200000c0, 0x200001c0); > if (res != -1) { > r[0] = res; > r[1] = *(uint64_t*)0x200000c0; > r[2] = *(uint64_t*)0x200001c0; > } > *(uint8_t*)0x20000180 = 0xb; > *(uint8_t*)0x20000181 = 1; > *(uint16_t*)0x20000182 = 0; > *(uint32_t*)0x20000184 = 0; > *(uint64_t*)0x20000188 = 4; > *(uint64_t*)0x20000190 = 0x20000140; > *(uint64_t*)0x20000140 = 0x77359400; > *(uint64_t*)0x20000148 = 0; > *(uint32_t*)0x20000198 = 1; > *(uint32_t*)0x2000019c = 0; > *(uint64_t*)0x200001a0 = 0; > *(uint16_t*)0x200001a8 = 0; > *(uint16_t*)0x200001aa = 0; > memset((void*)0x200001ac, 0, 20); > syz_io_uring_submit(r[1], r[2], 0x20000180, 1); > *(uint32_t*)0x20000544 = 0; > *(uint32_t*)0x20000548 = 0x36; > *(uint32_t*)0x2000054c = 0; > *(uint32_t*)0x20000550 = 0; > *(uint32_t*)0x20000558 = r[0]; > memset((void*)0x2000055c, 0, 12); > syz_io_uring_setup(0x4bf1, 0x20000540, 0x20ffd000, 0x20ffc000, 0, 0); > > } > int main(void) > { > syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul); > int pid = fork(); > if (pid < 0) > exit(1); > if (pid == 0) { > trigger_bug(); > exit(0); > } > int status = 0; > uint64_t start = current_time_ms(); > for (;;) { > if (current_time_ms() - start < 1000) { > continue; > } > kill_and_wait(pid, &status); > break; > } > return 0; > } > -- Pavel Begunkov
