Re: [syzbot] [net?] [bpf?] KMSAN: uninit-value in sock_hash_delete_elem

[syzbot <syzbot+c33bff5d5da1391df027@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in sock_hash_delete_elem

=====================================================
BUG: KMSAN: uninit-value in spin_lock_bh include/linux/spinlock.h:356 [inline]
BUG: KMSAN: uninit-value in sock_hash_delete_elem+0x490/0x690 net/core/sock_map.c:939
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 sock_hash_delete_elem+0x490/0x690 net/core/sock_map.c:939
 ____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:2011
 __bpf_prog_run32+0xb2/0xe0 kernel/bpf/core.c:2250
 bpf_dispatcher_nop_func include/linux/bpf.h:1233 [inline]
 __bpf_prog_run include/linux/filter.h:667 [inline]
 bpf_prog_run include/linux/filter.h:674 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2396 [inline]
 bpf_trace_run3+0x201/0x500 kernel/trace/bpf_trace.c:2438
 __bpf_trace_block_bio_remap+0x34/0x50 include/trace/events/block.h:507
 trace_block_bio_remap include/trace/events/block.h:507 [inline]
 blk_partition_remap block/blk-core.c:571 [inline]
 submit_bio_noacct+0x2449/0x2800 block/blk-core.c:762
 submit_bio+0x58a/0x5b0 block/blk-core.c:879
 submit_bh_wbc+0x81e/0x890 fs/buffer.c:2804
 submit_bh fs/buffer.c:2809 [inline]
 write_dirty_buffer+0x1ac/0x1f0 fs/buffer.c:2822
 flush_descriptor fs/jbd2/revoke.c:657 [inline]
 jbd2_journal_write_revoke_records+0x1c0b/0x1c80 fs/jbd2/revoke.c:562
 jbd2_journal_commit_transaction+0x1949/0xa620 fs/jbd2/commit.c:551
 kjournald2+0x494/0x900 fs/jbd2/journal.c:201
 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_run32+0x43/0xe0 kernel/bpf/core.c:2250
 bpf_dispatcher_nop_func include/linux/bpf.h:1233 [inline]
 __bpf_prog_run include/linux/filter.h:667 [inline]
 bpf_prog_run include/linux/filter.h:674 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2396 [inline]
 bpf_trace_run3+0x201/0x500 kernel/trace/bpf_trace.c:2438

CPU: 0 PID: 4418 Comm: jbd2/sda1-8 Not tainted 6.9.0-rc1-syzkaller-00257-ge478cf26c556 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
=====================================================


Tested on:

commit:         e478cf26 Merge branch 'bpf-fix-a-couple-of-test-failur..
git tree:       https://linux.googlesource.com/linux/kernel/git/torvalds/linux
console output: https://syzkaller.appspot.com/x/log.txt?x=1663af02980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e2599baf258ef795
dashboard link: https://syzkaller.appspot.com/bug?extid=c33bff5d5da1391df027
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.