syzbot


KMSAN: uninit-value in bch2_inode_unpack (2)

Status: upstream: reported on 2025/01/01 20:55
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+9b79c816ed3895539cf4@syzkaller.appspotmail.com
Fix commit: 9c3a2c9b471a bcachefs: Disable asm memcpys when kmsan enabled
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu-native-arm64-kvm ci-qemu2-arm32 ci-qemu2-riscv64]
First crash: 122d, last: 103d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bcachefs?] KMSAN: uninit-value in bch2_inode_unpack (2) 0 (2) 2025/04/01 03:58
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: uninit-value in bch2_inode_unpack bcachefs 187 323d 359d 0/28 auto-obsoleted due to no activity on 2024/08/20 07:49

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in bch2_inode_unpack_v3 fs/bcachefs/inode.c:274 [inline]
BUG: KMSAN: uninit-value in bch2_inode_unpack+0x9fb/0x4ca0 fs/bcachefs/inode.c:331
 bch2_inode_unpack_v3 fs/bcachefs/inode.c:274 [inline]
 bch2_inode_unpack+0x9fb/0x4ca0 fs/bcachefs/inode.c:331
 bch2_inode_rm+0xdbc/0x1260 fs/bcachefs/inode.c:1042
 bch2_evict_inode+0x2d5/0x6a0 fs/bcachefs/fs.c:1836
 evict+0x723/0xd10 fs/inode.c:796
 iput_final fs/inode.c:1946 [inline]
 iput+0x97b/0xdb0 fs/inode.c:1972
 bch2_symlink+0x49f/0x540 fs/bcachefs/fs.c:821
 vfs_symlink+0x1ed/0x460 fs/namei.c:4669
 do_symlinkat+0x253/0x8b0 fs/namei.c:4695
 __do_sys_symlink fs/namei.c:4716 [inline]
 __se_sys_symlink fs/namei.c:4714 [inline]
 __x64_sys_symlink+0xe0/0x140 fs/namei.c:4714
 x64_sys_call+0x31ca/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:89
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 memcpy_u64s_small fs/bcachefs/util.h:393 [inline]
 bkey_reassemble fs/bcachefs/bkey.h:513 [inline]
 btree_key_cache_create fs/bcachefs/btree_key_cache.c:259 [inline]
 btree_key_cache_fill+0xd1a/0x3d60 fs/bcachefs/btree_key_cache.c:309
 bch2_btree_path_traverse_cached+0x988/0xe20 fs/bcachefs/btree_key_cache.c:361
 bch2_btree_path_traverse_one+0x749/0x47b0 fs/bcachefs/btree_iter.c:1159
 bch2_btree_path_traverse fs/bcachefs/btree_iter.h:247 [inline]
 bch2_btree_iter_peek_slot+0x10b7/0x3950 fs/bcachefs/btree_iter.c:2629
 __bch2_bkey_get_iter fs/bcachefs/btree_iter.h:575 [inline]
 bch2_bkey_get_iter fs/bcachefs/btree_iter.h:589 [inline]
 bch2_inode_rm+0x95d/0x1260 fs/bcachefs/inode.c:1027
 bch2_evict_inode+0x2d5/0x6a0 fs/bcachefs/fs.c:1836
 evict+0x723/0xd10 fs/inode.c:796
 iput_final fs/inode.c:1946 [inline]
 iput+0x97b/0xdb0 fs/inode.c:1972
 bch2_symlink+0x49f/0x540 fs/bcachefs/fs.c:821
 vfs_symlink+0x1ed/0x460 fs/namei.c:4669
 do_symlinkat+0x253/0x8b0 fs/namei.c:4695
 __do_sys_symlink fs/namei.c:4716 [inline]
 __se_sys_symlink fs/namei.c:4714 [inline]
 __x64_sys_symlink+0xe0/0x140 fs/namei.c:4714
 x64_sys_call+0x31ca/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:89
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 ___kmalloc_large_node+0x22c/0x370 mm/slub.c:4253
 __kmalloc_large_node_noprof+0x3f/0x1e0 mm/slub.c:4270
 __do_kmalloc_node mm/slub.c:4286 [inline]
 __kmalloc_node_noprof+0xc96/0x1250 mm/slub.c:4304
 __kvmalloc_node_noprof+0xc0/0x2d0 mm/util.c:645
 btree_bounce_alloc fs/bcachefs/btree_io.c:124 [inline]
 btree_node_sort+0x78a/0x1d30 fs/bcachefs/btree_io.c:323
 bch2_btree_post_write_cleanup+0x1b0/0xf20 fs/bcachefs/btree_io.c:2248
 bch2_btree_node_write+0x21c/0x2e0 fs/bcachefs/btree_io.c:2289
 btree_node_write_if_need fs/bcachefs/btree_io.h:151 [inline]
 __btree_node_flush+0x606/0x680 fs/bcachefs/btree_trans_commit.c:252
 bch2_btree_node_flush0+0x35/0x60 fs/bcachefs/btree_trans_commit.c:261
 journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:565
 __bch2_journal_reclaim+0xda8/0x1670 fs/bcachefs/journal_reclaim.c:698
 bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:740
 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

CPU: 0 UID: 0 PID: 6869 Comm: syz.1.200 Not tainted 6.13.0-rc7-syzkaller-00102-gce69b4019001 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
=====================================================

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/17 09:56 upstream ce69b4019001 f9e07a6e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_inode_unpack
2025/01/17 03:50 upstream ce69b4019001 f9e07a6e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_inode_unpack
2025/01/11 15:53 upstream e0daef7de1ac 6dbc6a9b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_inode_unpack
2025/01/08 18:46 upstream 09a0fa92e5b4 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_inode_unpack
2025/01/05 11:09 upstream ab75170520d4 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_inode_unpack
2025/01/03 07:59 upstream 0bc21e701a6f d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_inode_unpack
2025/01/02 09:19 upstream 56e6a3499e14 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_inode_unpack
2025/01/01 17:10 upstream ccb98ccef0e5 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_inode_unpack
2024/12/28 20:52 upstream fd0584d220fe d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_inode_unpack
* Struck through repros no longer work on HEAD.