On Tue, 2 May 2023 at 09:05, syzbot <syzbot+01e9a564dc6b3289cea3@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > 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 +riscv maintainers I think this is an issue in riscv stack walking. If it's imprecise or walks stacks of running tasks, it needs to use READ_ONCE_NOCHECK. #syz set subsystems: riscv > [<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 > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/00000000000084706805fab08e27%40google.com.
