On Sun, Jun 16, 2024 at 4:43 AM syzbot wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 614da38e2f7a Merge tag 'hid-for-linus-2024051401' of git:/.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=12d26ada980000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f5d2cbf33633f507 > dashboard link: https://syzkaller.appspot.com/bug?extid=206133fb2e7b32bba4be > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/89eafb874b71/disk-614da38e.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/356000512ad9/vmlinux-614da38e.xz > kernel image: https://storage.googleapis.com/syzbot-assets/839c73939115/bzImage-614da38e.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+206133fb2e7b32bba4be@xxxxxxxxxxxxxxxxxxxxxxxxx > > ===================================================== > BUG: KMSAN: uninit-value in crc32_body lib/crc32.c:110 [inline] > BUG: KMSAN: uninit-value in crc32_le_generic lib/crc32.c:179 [inline] > BUG: KMSAN: uninit-value in crc32_le_base+0x43c/0xd80 lib/crc32.c:197 > crc32_body lib/crc32.c:110 [inline] > crc32_le_generic lib/crc32.c:179 [inline] > crc32_le_base+0x43c/0xd80 lib/crc32.c:197 > nilfs_segbuf_fill_in_data_crc fs/nilfs2/segbuf.c:224 [inline] > nilfs_add_checksums_on_logs+0xb80/0xe40 fs/nilfs2/segbuf.c:327 > nilfs_segctor_do_construct+0x9876/0xdeb0 fs/nilfs2/segment.c:2078 > nilfs_segctor_construct+0x1eb/0xe30 fs/nilfs2/segment.c:2381 > nilfs_segctor_thread_construct fs/nilfs2/segment.c:2489 [inline] > nilfs_segctor_thread+0xc50/0x11e0 fs/nilfs2/segment.c:2573 > kthread+0x3e2/0x540 kernel/kthread.c:389 > ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > Uninit was stored to memory at: > memcpy_from_iter lib/iov_iter.c:73 [inline] > iterate_bvec include/linux/iov_iter.h:122 [inline] > iterate_and_advance2 include/linux/iov_iter.h:249 [inline] > iterate_and_advance include/linux/iov_iter.h:271 [inline] > __copy_from_iter lib/iov_iter.c:249 [inline] > copy_page_from_iter_atomic+0x12b7/0x2ae0 lib/iov_iter.c:481 > generic_perform_write+0x4c1/0xc60 mm/filemap.c:3982 > __generic_file_write_iter+0x20a/0x460 mm/filemap.c:4069 > generic_file_write_iter+0x103/0x5b0 mm/filemap.c:4095 > __kernel_write_iter+0x64d/0xc80 fs/read_write.c:523 > dump_emit_page fs/coredump.c:895 [inline] > dump_user_range+0x8dc/0xee0 fs/coredump.c:956 > elf_core_dump+0x57c7/0x5ae0 fs/binfmt_elf.c:2083 > do_coredump+0x32d5/0x4920 fs/coredump.c:769 > get_signal+0x267e/0x2d00 kernel/signal.c:2896 > arch_do_signal_or_restart+0x53/0xcb0 arch/x86/kernel/signal.c:310 > exit_to_user_mode_loop kernel/entry/common.c:111 [inline] > exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] > __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] > syscall_exit_to_user_mode+0x5d/0x160 kernel/entry/common.c:218 > do_syscall_64+0xdc/0x1e0 arch/x86/entry/common.c:89 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Uninit was created at: > __alloc_pages+0x9d6/0xe70 mm/page_alloc.c:4598 > alloc_pages_mpol+0x299/0x990 mm/mempolicy.c:2264 > alloc_pages+0x1bf/0x1e0 mm/mempolicy.c:2335 > dump_user_range+0x4a/0xee0 fs/coredump.c:940 > elf_core_dump+0x57c7/0x5ae0 fs/binfmt_elf.c:2083 > do_coredump+0x32d5/0x4920 fs/coredump.c:769 > get_signal+0x267e/0x2d00 kernel/signal.c:2896 > arch_do_signal_or_restart+0x53/0xcb0 arch/x86/kernel/signal.c:310 > exit_to_user_mode_loop kernel/entry/common.c:111 [inline] > exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] > __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] > syscall_exit_to_user_mode+0x5d/0x160 kernel/entry/common.c:218 > do_syscall_64+0xdc/0x1e0 arch/x86/entry/common.c:89 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > CPU: 0 PID: 5368 Comm: segctord Not tainted 6.9.0-syzkaller-02707-g614da38e2f7a #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 > ===================================================== > > > --- > 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 report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup Ah, this issue appears to be the same as the following issue where a memory dump generated by elf_core_dump() gets mixed into the filesystem: https://syzkaller.appspot.com/bug?extid=47a017c46edb25eff048 However, the kernel that syzbot tested had the common fix for this issue, commit 61b258b0d2f6 ("x86: call instrumentation hooks from copy_mc.c") applied. So the patch may not have fixed the issue. Ryusuke Konishi
