syzbot


KMSAN: uninit-value in percpu_array_map_lookup_percpu_elem

Status: closed as dup on 2024/04/03 17:55
Subsystems: bpf
[Documentation on labels]
Reported-by: syzbot+aca389a8a7da35c070ce@syzkaller.appspotmail.com
First crash: 17d, last: 13d
Duplicate of
Title Repro Cause bisect Fix bisect Count Last Reported
KMSAN: uninit-value in dev_map_lookup_elem bpf net C 3 15d 22d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bpf?] KMSAN: uninit-value in percpu_array_map_lookup_percpu_elem 1 (2) 2024/04/03 17:55

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in percpu_array_map_lookup_percpu_elem+0x1cb/0x200 kernel/bpf/arraymap.c:257
 percpu_array_map_lookup_percpu_elem+0x1cb/0x200 kernel/bpf/arraymap.c:257
 ____bpf_map_lookup_percpu_elem kernel/bpf/helpers.c:133 [inline]
 bpf_map_lookup_percpu_elem+0x67/0x90 kernel/bpf/helpers.c:130
 ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
 __bpf_prog_run288+0xb5/0xe0 kernel/bpf/core.c:2237
 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_run8+0x1bd/0x3a0 kernel/trace/bpf_trace.c:2426
 __bpf_trace_jbd2_handle_stats+0x51/0x70 include/trace/events/jbd2.h:210
 trace_jbd2_handle_stats include/trace/events/jbd2.h:210 [inline]
 jbd2_journal_stop+0x1157/0x12c0 fs/jbd2/transaction.c:1869
 __ext4_journal_stop+0x115/0x310 fs/ext4/ext4_jbd2.c:134
 ext4_do_writepages+0x1c3c/0x62e0 fs/ext4/inode.c:2692
 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:243

Local variable stack created at:
 __bpf_prog_run288+0x45/0xe0 kernel/bpf/core.c:2237
 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_run8+0x1bd/0x3a0 kernel/trace/bpf_trace.c:2426

CPU: 1 PID: 1070 Comm: kworker/u8:7 Not tainted 6.9.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: writeback wb_workfn (flush-8:0)
=====================================================

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/01 23:28 upstream 39cd87c4eb2b 6baf5069 .config strace log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in percpu_array_map_lookup_percpu_elem
2024/04/03 19:58 upstream 3e92c1e6cd87 fed899ed .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in percpu_array_map_lookup_percpu_elem
2024/04/01 21:38 upstream 39cd87c4eb2b 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in percpu_array_map_lookup_percpu_elem
2024/04/01 21:42 upstream 39cd87c4eb2b 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in percpu_array_map_lookup_percpu_elem
2024/03/29 22:31 upstream 317c7bc0ef03 c52bcb23 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in percpu_array_map_lookup_percpu_elem
* Struck through repros no longer work on HEAD.