Hello, syzbot found the following issue on: HEAD commit: 950b879b7f02 riscv: Fixup race condition on PG_dcache_clea.. 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=10c4c1f7c80000 kernel config: https://syzkaller.appspot.com/x/.config?x=ecebece1b90c0342 dashboard link: https://syzkaller.appspot.com/bug?extid=01e9a564dc6b3289cea3 compiler: riscv64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 userspace arch: riscv64 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+01e9a564dc6b3289cea3@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: stack-out-of-bounds in walk_stackframe+0x128/0x2fe arch/riscv/kernel/stacktrace.c:58 Read of size 8 at addr ff200000030a79b0 by task syz-executor.1/7894 CPU: 0 PID: 7894 Comm: syz-executor.1 Tainted: G W 6.2.0-rc1-syzkaller #0 Hardware name: riscv-virtio,qemu (DT) Call Trace: [<ffffffff8000b9ea>] dump_backtrace+0x2e/0x3c arch/riscv/kernel/stacktrace.c:121 [<ffffffff83402b96>] show_stack+0x34/0x40 arch/riscv/kernel/stacktrace.c:127 [<ffffffff83442726>] __dump_stack lib/dump_stack.c:88 [inline] [<ffffffff83442726>] dump_stack_lvl+0xe0/0x14c lib/dump_stack.c:106 [<ffffffff83409674>] print_address_description mm/kasan/report.c:306 [inline] [<ffffffff83409674>] print_report+0x1e4/0x4c0 mm/kasan/report.c:417 [<ffffffff804ead14>] kasan_report+0xb8/0xe6 mm/kasan/report.c:517 [<ffffffff804ebea4>] check_region_inline mm/kasan/generic.c:183 [inline] [<ffffffff804ebea4>] __asan_load8+0x7e/0xa6 mm/kasan/generic.c:256 [<ffffffff8000b782>] walk_stackframe+0x128/0x2fe arch/riscv/kernel/stacktrace.c:58 [<ffffffff8000bc66>] arch_stack_walk+0x2c/0x3c arch/riscv/kernel/stacktrace.c:154 [<ffffffff80190822>] stack_trace_save_tsk+0x14a/0x1bc kernel/stacktrace.c:150 [<ffffffff80697822>] proc_pid_stack+0x146/0x1ee fs/proc/base.c:456 [<ffffffff80698bb0>] proc_single_show+0x9c/0x148 fs/proc/base.c:777 [<ffffffff805af580>] traverse.part.0+0x74/0x2ca fs/seq_file.c:111 [<ffffffff805aff02>] traverse fs/seq_file.c:101 [inline] [<ffffffff805aff02>] seq_read_iter+0x72c/0x934 fs/seq_file.c:195 [<ffffffff805b0224>] seq_read+0x11a/0x16e fs/seq_file.c:162 [<ffffffff805453ea>] do_loop_readv_writev fs/read_write.c:756 [inline] [<ffffffff805453ea>] do_loop_readv_writev fs/read_write.c:743 [inline] [<ffffffff805453ea>] do_iter_read+0x324/0x3c2 fs/read_write.c:798 [<ffffffff805455f8>] vfs_readv+0xfe/0x166 fs/read_write.c:916 [<ffffffff80549c66>] do_preadv fs/read_write.c:1008 [inline] [<ffffffff80549c66>] __do_sys_preadv fs/read_write.c:1058 [inline] [<ffffffff80549c66>] sys_preadv+0x182/0x1fa fs/read_write.c:1053 [<ffffffff80005ff6>] ret_from_syscall+0x0/0x2 The buggy address belongs to the virtual mapping at [ff200000030a0000, ff200000030a9000) created by: kernel_clone+0xee/0x914 kernel/fork.c:2681 The buggy address belongs to the physical page: page:ff1c0000024e5f00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9397c memcg:ff6000000ffd7202 flags: 0xffe000000000000(node=0|zone=0|lastcpupid=0x7ff) raw: 0ffe000000000000 0000000000000000 0000000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff ff6000000ffd7202 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 7873, tgid 7873 (syz-executor.1), ts 4012100669800, free_ts 4010400733200 __set_page_owner+0x32/0x182 mm/page_owner.c:190 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0xf8/0x11a mm/page_alloc.c:2524 prep_new_page mm/page_alloc.c:2531 [inline] get_page_from_freelist+0xc0e/0x1118 mm/page_alloc.c:4283 __alloc_pages+0x1b0/0x165a mm/page_alloc.c:5549 alloc_pages+0x132/0x25e mm/mempolicy.c:2286 vm_area_alloc_pages mm/vmalloc.c:2989 [inline] __vmalloc_area_node mm/vmalloc.c:3057 [inline] __vmalloc_node_range+0x81c/0xdb4 mm/vmalloc.c:3227 alloc_thread_stack_node kernel/fork.c:311 [inline] dup_task_struct kernel/fork.c:987 [inline] copy_process+0x210e/0x4068 kernel/fork.c:2097 kernel_clone+0xee/0x914 kernel/fork.c:2681 __do_sys_clone+0xec/0x120 kernel/fork.c:2822 sys_clone+0x32/0x44 kernel/fork.c:2790 ret_from_syscall+0x0/0x2 page last free stack trace: __reset_page_owner+0x4a/0xf8 mm/page_owner.c:148 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1446 [inline] free_pcp_prepare+0x254/0x48e mm/page_alloc.c:1496 free_unref_page_prepare mm/page_alloc.c:3369 [inline] free_unref_page_list+0x11e/0x736 mm/page_alloc.c:3510 release_pages+0x85a/0xbb2 mm/swap.c:1076 free_pages_and_swap_cache+0x76/0x88 mm/swap_state.c:311 tlb_batch_pages_flush+0x86/0x10c mm/mmu_gather.c:97 tlb_flush_mmu_free mm/mmu_gather.c:292 [inline] tlb_flush_mmu mm/mmu_gather.c:299 [inline] tlb_finish_mmu+0xcc/0x280 mm/mmu_gather.c:391 exit_mmap+0x190/0x686 mm/mmap.c:3096 __mmput+0x98/0x290 kernel/fork.c:1207 mmput+0x74/0x88 kernel/fork.c:1229 exit_mm kernel/exit.c:563 [inline] do_exit+0x602/0x17be kernel/exit.c:854 do_group_exit+0x8e/0x15e kernel/exit.c:1012 __do_sys_exit_group kernel/exit.c:1023 [inline] __wake_up_parent+0x0/0x4a kernel/exit.c:1021 ret_from_syscall+0x0/0x2 Memory state around the buggy address: ff200000030a7880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ff200000030a7900: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 f2 f2 >ff200000030a7980: 00 00 00 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00 ^ ff200000030a7a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ff200000030a7a80: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 ================================================================== --- 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 syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the bug is already fixed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to change bug's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the bug is a duplicate of another bug, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
