syzbot


KMSAN: uninit-value in bch2_alloc_sectors_start_trans (2)

Status: upstream: reported syz repro on 2025/04/16 17:47
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+2caec1f3fc52004d4f3c@syzkaller.appspotmail.com
Fix commit: bcachefs: Add missing ei_last_dirtied update
Patched on: [ci-upstream-linux-next-kasan-gce-root ci-upstream-rust-kasan-gce], missing on: [ci-qemu-gce-upstream-auto ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 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-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb]
First crash: 159d, last: 4d15h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bcachefs?] KMSAN: uninit-value in bch2_alloc_sectors_start_trans (2) 0 (3) 2025/07/23 10:59
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: uninit-value in bch2_alloc_sectors_start_trans bcachefs 7 C 101 250d 281d 0/29 auto-obsoleted due to no activity on 2025/03/22 13:38

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in __writepoint_find fs/bcachefs/alloc_foreground.c:1171 [inline]
BUG: KMSAN: uninit-value in writepoint_find fs/bcachefs/alloc_foreground.c:1248 [inline]
BUG: KMSAN: uninit-value in bch2_alloc_sectors_start_trans+0x4d0/0x3630 fs/bcachefs/alloc_foreground.c:1348
 __writepoint_find fs/bcachefs/alloc_foreground.c:1171 [inline]
 writepoint_find fs/bcachefs/alloc_foreground.c:1248 [inline]
 bch2_alloc_sectors_start_trans+0x4d0/0x3630 fs/bcachefs/alloc_foreground.c:1348
 __bch2_write+0x802/0x6bf0 fs/bcachefs/io_write.c:1515
 bch2_write+0xe9f/0x1690 fs/bcachefs/io_write.c:1702
 closure_queue include/linux/closure.h:270 [inline]
 closure_call include/linux/closure.h:432 [inline]
 bch2_writepage_do_io fs/bcachefs/fs-io-buffered.c:494 [inline]
 bch2_writepages+0x22d/0x430 fs/bcachefs/fs-io-buffered.c:677
 do_writepages+0x448/0xcb0 mm/page-writeback.c:2656
 __writeback_single_inode+0x101/0x1190 fs/fs-writeback.c:1680
 writeback_sb_inodes+0xaa9/0x1c90 fs/fs-writeback.c:1976
 wb_writeback+0x4ce/0xc00 fs/fs-writeback.c:2156
 wb_do_writeback fs/fs-writeback.c:2303 [inline]
 wb_workfn+0x397/0x1910 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd59/0xf00 kernel/kthread.c:464
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was stored to memory at:
 bch2_writepage_io_alloc fs/bcachefs/fs-io-buffered.c:522 [inline]
 __bch2_writepage+0x2b49/0x3c70 fs/bcachefs/fs-io-buffered.c:644
 write_cache_pages+0xc8/0x270 mm/page-writeback.c:2613
 bch2_writepages+0x121/0x430 fs/bcachefs/fs-io-buffered.c:675
 do_writepages+0x448/0xcb0 mm/page-writeback.c:2656
 __writeback_single_inode+0x101/0x1190 fs/fs-writeback.c:1680
 writeback_sb_inodes+0xaa9/0x1c90 fs/fs-writeback.c:1976
 wb_writeback+0x4ce/0xc00 fs/fs-writeback.c:2156
 wb_do_writeback fs/fs-writeback.c:2303 [inline]
 wb_workfn+0x397/0x1910 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd59/0xf00 kernel/kthread.c:464
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4153 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 kmem_cache_alloc_lru_noprof+0x822/0xed0 mm/slub.c:4215
 __bch2_new_inode+0x9b/0x4b0 fs/bcachefs/fs.c:457
 bch2_new_inode fs/bcachefs/fs.c:483 [inline]
 bch2_inode_hash_init_insert+0x82/0x3c0 fs/bcachefs/fs.c:503
 bch2_vfs_inode_get+0x565/0x710 fs/bcachefs/fs.c:526
 bch2_fs_get_tree+0x1dde/0x2820 fs/bcachefs/fs.c:2576
 vfs_get_tree+0xb0/0x5c0 fs/super.c:1759
 do_new_mount+0x738/0x1610 fs/namespace.c:3881
 path_mount+0x6db/0x1e90 fs/namespace.c:4208
 do_mount fs/namespace.c:4221 [inline]
 __do_sys_mount fs/namespace.c:4432 [inline]
 __se_sys_mount+0x6eb/0x7d0 fs/namespace.c:4409
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4409
 x64_sys_call+0xfa7/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x1b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 5972 Comm: kworker/u8:4 Not tainted 6.15.0-rc6-syzkaller-00278-g172a9d94339c #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: writeback wb_workfn (flush-bcachefs-17)
=====================================================

Crashes (808):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/17 23:35 upstream 172a9d94339c f41472b0 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/14 08:28 upstream 5cd64d4f9268 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/12 19:31 upstream 320475fbd590 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/12 04:05 upstream 02ffd6f89c50 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/12 04:04 upstream 02ffd6f89c50 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/11 13:44 upstream 7aac71907bde fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/11 11:02 upstream 7aac71907bde fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/10 20:44 upstream 9dd1835ecda5 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/10 16:31 upstream 9dd1835ecda5 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/10 13:07 upstream 9dd1835ecda5 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/10 09:12 upstream 9dd1835ecda5 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/10 00:50 upstream 9dd1835ecda5 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/09 13:28 upstream f777d1112ee5 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/09 07:54 upstream f777d1112ee5 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/09 07:45 upstream f777d1112ee5 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/09 04:43 upstream f777d1112ee5 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/08 22:19 upstream f777d1112ee5 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/08 18:16 upstream 76eeb9b8de98 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/08 17:44 upstream 76eeb9b8de98 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/08 05:51 upstream 6ab41fca2e80 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/08 04:49 upstream 6ab41fca2e80 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/08 04:36 upstream 6ab41fca2e80 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/07 19:21 upstream 6ab41fca2e80 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/07 16:16 upstream b236920731dd d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/07 14:25 upstream b236920731dd d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/06 07:12 upstream c8ed9b5c02a5 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/05 11:17 upstream d69eb204c255 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/03 19:17 upstream e6b9dce0aeeb 96a211bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/03 13:15 upstream e6b9dce0aeeb 96a211bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/03 04:48 upstream e6b9dce0aeeb 091ba174 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/03 01:19 upstream e6b9dce0aeeb 091ba174 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/02 19:53 upstream b320789d6883 091ba174 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/02 16:22 upstream b320789d6883 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/02 12:48 upstream b320789d6883 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/02 10:37 upstream b320789d6883 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/02 02:24 upstream b320789d6883 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/01 22:56 upstream b320789d6883 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/01 19:48 upstream b320789d6883 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/01 16:20 upstream b320789d6883 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/01 11:34 upstream b320789d6883 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/01 07:17 upstream 5c3b3264e585 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/01 04:56 upstream 5c3b3264e585 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/09/01 01:01 upstream 5c3b3264e585 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/08/31 21:36 upstream 5c3b3264e585 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/08/31 21:36 upstream 5c3b3264e585 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/04/16 12:57 upstream 1a1d569a75f3 23b969b7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
2025/04/12 17:46 upstream 3bde70a2c827 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in bch2_alloc_sectors_start_trans
* Struck through repros no longer work on HEAD.