[syzbot] KASAN: null-ptr-deref Read in ida_free (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 08897940f458 Add linux-next specific files for 20220623
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=14fc8c60080000
kernel config: https://syzkaller.appspot.com/x/.config?x=fb185a52c6ad0a8e
dashboard link: https://syzkaller.appspot.com/bug?extid=aa620fb1ece874a3f34c
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=116b4140080000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17ab12e4080000

The issue was bisected to:

commit f2d8c2606825317b77db1f9ba0fc26ef26160b30
Author: Alan Stern <st...@rowland.harvard.edu>
Date: Mon Jun 13 14:17:03 2022 +0000

usb: gadget: Fix non-unique driver names in raw-gadget driver

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15b40318080000
final oops: https://syzkaller.appspot.com/x/report.txt?x=17b40318080000
console output: https://syzkaller.appspot.com/x/log.txt?x=13b40318080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+aa620f...@syzkaller.appspotmail.com
Fixes: f2d8c2606825 ("usb: gadget: Fix non-unique driver names in raw-gadget driver")

==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: null-ptr-deref in test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
BUG: KASAN: null-ptr-deref in ida_free+0x1b6/0x2e0 lib/idr.c:510
Read of size 8 at addr 0000000000000000 by task syz-executor185/3627

CPU: 1 PID: 3627 Comm: syz-executor185 Not tainted 5.19.0-rc3-next-20220623-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
kasan_report+0xbe/0x1f0 mm/kasan/report.c:495
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
instrument_atomic_read include/linux/instrumented.h:71 [inline]
test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
ida_free+0x1b6/0x2e0 lib/idr.c:510
dev_free+0xec/0x700 drivers/usb/gadget/legacy/raw_gadget.c:212
kref_put include/linux/kref.h:65 [inline]
raw_release+0x219/0x290 drivers/usb/gadget/legacy/raw_gadget.c:424
__fput+0x277/0x9d0 fs/file_table.c:317
task_work_run+0xdd/0x1a0 kernel/task_work.c:177
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xb05/0x2a00 kernel/exit.c:795
do_group_exit+0xd2/0x2f0 kernel/exit.c:925
__do_sys_exit_group kernel/exit.c:936 [inline]
__se_sys_exit_group kernel/exit.c:934 [inline]
__x64_sys_exit_group+0x3a/0x50 kernel/exit.c:934
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f12d28b6bd9
Code: Unable to access opcode bytes at RIP 0x7f12d28b6baf.
RSP: 002b:00007ffea2859da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f12d292b3f0 RCX: 00007f12d28b6bd9
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 000000000000000b
R10: 00007ffea2857e00 R11: 0000000000000246 R12: 00007f12d292b3f0
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
</TASK>
==================================================================


---
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[Alan Stern]

This should be fixed by the patch that was just merged.

Alan Stern

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git 90bc2af24638

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+aa620f...@syzkaller.appspotmail.com

Tested on:

commit: 90bc2af2 USB: gadget: Fix double-free bug in raw_gadge..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
console output: https://syzkaller.appspot.com/x/log.txt?x=102c524c080000
kernel config: https://syzkaller.appspot.com/x/.config?x=34c24e9249d527bb

dashboard link: https://syzkaller.appspot.com/bug?extid=aa620fb1ece874a3f34c
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Note: no patches were applied.
Note: testing is done by a robot and is best-effort only.

[Siddh Raman Pant]

Since this is fixed, marking it as such.

#syz fix: USB: gadget: Fix double-free bug in raw_gadget driver