syzbot


KMSAN: uninit-value in htab_map_delete_elem

Status: upstream: reported syz repro on 2024/04/27 08:34
Subsystems: bpf
[Documentation on labels]
Reported-by: syzbot+9b0b6780e063c00f1453@syzkaller.appspotmail.com
First crash: 59d, last: 55d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bpf?] KMSAN: uninit-value in htab_map_delete_elem 0 (1) 2024/04/27 08:34
Last patch testing requests (1)
Created Duration User Patch Repo Result
2024/05/11 17:26 25m retest repro upstream OK log

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in lookup_elem_raw kernel/bpf/hashtab.c:642 [inline]
BUG: KMSAN: uninit-value in htab_map_delete_elem+0x492/0xaf0 kernel/bpf/hashtab.c:1427
 lookup_elem_raw kernel/bpf/hashtab.c:642 [inline]
 htab_map_delete_elem+0x492/0xaf0 kernel/bpf/hashtab.c:1427
 ____bpf_map_delete_elem kernel/bpf/helpers.c:77 [inline]
 bpf_map_delete_elem+0x5c/0x80 kernel/bpf/helpers.c:73
 ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
 __bpf_prog_run160+0xb5/0xe0 kernel/bpf/core.c:2236
 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
 __bpf_prog_run include/linux/filter.h:657 [inline]
 bpf_prog_run include/linux/filter.h:664 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
 bpf_trace_run4+0x150/0x340 kernel/trace/bpf_trace.c:2422
 __bpf_trace_ext4_writepages_result+0x3c/0x50 include/trace/events/ext4.h:542
 __traceiter_ext4_writepages_result+0xad/0x160 include/trace/events/ext4.h:542
 trace_ext4_writepages_result include/trace/events/ext4.h:542 [inline]
 ext4_do_writepages+0x6109/0x62e0 fs/ext4/inode.c:2747
 ext4_writepages+0x312/0x830 fs/ext4/inode.c:2768
 do_writepages+0x427/0xc30 mm/page-writeback.c:2612
 __writeback_single_inode+0x10d/0x12c0 fs/fs-writeback.c:1650
 writeback_sb_inodes+0xb48/0x1be0 fs/fs-writeback.c:1941
 __writeback_inodes_wb+0x14c/0x440 fs/fs-writeback.c:2012
 wb_writeback+0x4da/0xdf0 fs/fs-writeback.c:2119
 wb_check_old_data_flush fs/fs-writeback.c:2223 [inline]
 wb_do_writeback fs/fs-writeback.c:2276 [inline]
 wb_workfn+0x110c/0x1940 fs/fs-writeback.c:2304
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa81/0x1bd0 kernel/workqueue.c:3335
 worker_thread+0xea5/0x1560 kernel/workqueue.c:3416
 kthread+0x3e2/0x540 kernel/kthread.c:388
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Local variable stack created at:
 __bpf_prog_run160+0x45/0xe0 kernel/bpf/core.c:2236
 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
 __bpf_prog_run include/linux/filter.h:657 [inline]
 bpf_prog_run include/linux/filter.h:664 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
 bpf_trace_run4+0x150/0x340 kernel/trace/bpf_trace.c:2422

CPU: 0 PID: 60 Comm: kworker/u8:5 Not tainted 6.9.0-rc5-syzkaller-00042-ge88c4cfcb7b8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: writeback wb_workfn (flush-8:0)
=====================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/25 10:35 upstream e88c4cfcb7b8 8bdc0f22 .config console log report syz [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in htab_map_delete_elem
2024/04/23 08:26 upstream 4d2008430ce8 21339d7b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in htab_map_delete_elem
2024/04/27 09:42 upstream 5eb4573ea63d 07b455f9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in htab_map_delete_elem
* Struck through repros no longer work on HEAD.