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Date: Thu, 18 Jan 2024 14:02:52 +0000
From: Matthew Wilcox <willy@infradead.org>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: syzbot <syzbot+51baee846ddab52d5230@syzkaller.appspotmail.com>,
	wzhmmmmm@gmail.com, johan.hedberg@gmail.com,
	linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org,
	luiz.dentz@gmail.com, marcel@holtmann.org,
	syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [bluetooth?] KASAN: null-ptr-deref Read in ida_free (4)
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On Thu, Jan 18, 2024 at 11:21:34AM +0100, Dmitry Vyukov wrote:
> On Sat, 25 Nov 2023 at 14:18, syzbot
> <syzbot+51baee846ddab52d5230@syzkaller.appspotmail.com> wrote:
> >
> > syzbot has found a reproducer for the following issue on:
> >
> > HEAD commit:    8c9660f65153 Add linux-next specific files for 20231124
> > git tree:       linux-next
> > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1678a3cce80000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=ca1e8655505e280
> > dashboard link: https://syzkaller.appspot.com/bug?extid=51baee846ddab52d5230
> > compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10d54c08e80000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=160ef1a4e80000
> >
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/345ed4af3a0d/disk-8c9660f6.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/191053c69d57/vmlinux-8c9660f6.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/aac7ee5e55e0/bzImage-8c9660f6.xz
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+51baee846ddab52d5230@syzkaller.appspotmail.com
> >
> > Bluetooth: hci0: hardware error 0x00
> > ==================================================================
> > BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:68 [inline]
> > BUG: KASAN: null-ptr-deref in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
> > BUG: KASAN: null-ptr-deref in ida_free+0x218/0x2e0 lib/idr.c:511
> > Read of size 8 at addr 0000000000000078 by task kworker/u5:1/4455
> >
> > CPU: 1 PID: 4455 Comm: kworker/u5:1 Not tainted 6.7.0-rc2-next-20231124-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
> > Workqueue: hci0 hci_error_reset
> > Call Trace:
> >  <TASK>
> >  __dump_stack lib/dump_stack.c:88 [inline]
> >  dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
> >  kasan_report+0xd9/0x110 mm/kasan/report.c:588
> >  check_region_inline mm/kasan/generic.c:182 [inline]
> >  kasan_check_range+0xef/0x190 mm/kasan/generic.c:188
> >  instrument_atomic_read include/linux/instrumented.h:68 [inline]
> >  _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
> 
> Wonder if this is fixed with:
> 
> ida: Fix crash in ida_free when the bitmap is empty
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=af73483f4e8b6f5c68c9aa63257bdd929a9c194a
> 
> ?

Should be.  The backtrace below looks like it's the same bug that got
reported 3-4 weeks ago.

> >  ida_free+0x218/0x2e0 lib/idr.c:511
> >  hci_conn_cleanup net/bluetooth/hci_conn.c:157 [inline]
> >  hci_conn_del+0x78c/0xe10 net/bluetooth/hci_conn.c:1183
> >  hci_conn_hash_flush+0x189/0x260 net/bluetooth/hci_conn.c:2643
> >  hci_dev_close_sync+0x5a7/0x1160 net/bluetooth/hci_sync.c:5021
> >  hci_dev_do_close+0x2e/0x90 net/bluetooth/hci_core.c:554
> >  hci_error_reset+0xa6/0x190 net/bluetooth/hci_core.c:1059
> >  process_one_work+0x8a4/0x15f0 kernel/workqueue.c:2633
> >  process_scheduled_works kernel/workqueue.c:2706 [inline]
> >  worker_thread+0x8b6/0x1290 kernel/workqueue.c:2787
> >  kthread+0x2c1/0x3a0 kernel/kthread.c:389
> >  ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
> >  ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
> >  </TASK>
> > ==================================================================
> >
> >
> > ---
> > If you want syzbot to run the reproducer, reply with:
> > #syz test: git://repo/address.git branch-or-commit-hash
> > If you attach or paste a git patch, syzbot will apply it before testing.
> >
> > --
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