syzbot


KMSAN: uninit-value in btree_interior_update_work

Status: upstream: reported on 2025/01/29 09:17
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+de02219c78c082fe2f21@syzkaller.appspotmail.com
Fix commit: 1f88c3567495 bcachefs: Fix a KMSAN splat in btree_update_nodes_written()
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: 82d, last: 26d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bcachefs?] KMSAN: uninit-value in btree_interior_update_work 0 (2) 2025/04/01 03:57

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in btree_update_nodes_written fs/bcachefs/btree_update_interior.c:690 [inline]
BUG: KMSAN: uninit-value in btree_interior_update_work+0xcae/0x4830 fs/bcachefs/btree_update_interior.c:846
 btree_update_nodes_written fs/bcachefs/btree_update_interior.c:690 [inline]
 btree_interior_update_work+0xcae/0x4830 fs/bcachefs/btree_update_interior.c:846
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xc1a/0x1e80 kernel/workqueue.c:3319
 worker_thread+0xea7/0x14f0 kernel/workqueue.c:3400
 kthread+0x6b9/0xef0 kernel/kthread.c:464
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was created at:
 ___kmalloc_large_node+0x22c/0x370 mm/slub.c:4249
 __kmalloc_large_node_noprof+0x3f/0x1e0 mm/slub.c:4266
 __do_kmalloc_node mm/slub.c:4282 [inline]
 __kmalloc_node_noprof+0xc96/0x1250 mm/slub.c:4300
 __kvmalloc_node_noprof+0xc0/0x2d0 mm/util.c:665
 btree_node_data_alloc fs/bcachefs/btree_cache.c:156 [inline]
 bch2_btree_node_mem_alloc+0xa96/0x2f10 fs/bcachefs/btree_cache.c:835
 __bch2_btree_node_alloc fs/bcachefs/btree_update_interior.c:304 [inline]
 bch2_btree_reserve_get+0x37f/0x2290 fs/bcachefs/btree_update_interior.c:532
 bch2_btree_update_start+0x2b0e/0x2d60 fs/bcachefs/btree_update_interior.c:1251
 bch2_btree_split_leaf+0x120/0xc90 fs/bcachefs/btree_update_interior.c:1853
 bch2_trans_commit_error+0x1c0/0x1d60 fs/bcachefs/btree_trans_commit.c:908
 __bch2_trans_commit+0x1d5f/0xd310 fs/bcachefs/btree_trans_commit.c:1089
 bch2_trans_commit fs/bcachefs/btree_update.h:191 [inline]
 bch2_journal_replay+0x3125/0x4e20 fs/bcachefs/recovery.c:373
 bch2_run_recovery_pass fs/bcachefs/recovery_passes.c:226 [inline]
 bch2_run_recovery_passes+0x5a2/0x1160 fs/bcachefs/recovery_passes.c:291
 bch2_fs_recovery+0x489c/0x6230 fs/bcachefs/recovery.c:936
 bch2_fs_start+0x7ca/0xc20 fs/bcachefs/super.c:1041
 bch2_fs_get_tree+0x1564/0x24e0 fs/bcachefs/fs.c:2203
 vfs_get_tree+0xb1/0x5a0 fs/super.c:1814
 do_new_mount+0x71f/0x15e0 fs/namespace.c:3560
 path_mount+0x742/0x1f10 fs/namespace.c:3887
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount+0x71f/0x800 fs/namespace.c:4088
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4088
 x64_sys_call+0x39bf/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:166
 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

CPU: 0 UID: 0 PID: 3636 Comm: kworker/u8:14 Tainted: G        W          6.14.0-rc7-syzkaller-00196-g88d324e69ea9 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: btree_update btree_interior_update_work
=====================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/22 14:35 upstream 88d324e69ea9 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in btree_interior_update_work
2025/01/25 09:10 upstream ab18b8fff124 9fbd772e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in btree_interior_update_work
* Struck through repros no longer work on HEAD.