linux-next test error: BUG: using smp_processor_id() in preemptible [ADDR] code: systemd-rfkill/6728

syzbot

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Jun 4, 2020, 10:02:20 PM6/4/20

to adilger...@dilger.ca, linux...@vger.kernel.org, linux-...@vger.kernel.org, linux...@vger.kernel.org, s...@canb.auug.org.au, syzkall...@googlegroups.com, ty...@mit.edu

Hello,

syzbot found the following crash on:

HEAD commit: 0e21d462 Add linux-next specific files for 20200602
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10461661100000
kernel config: https://syzkaller.appspot.com/x/.config?x=ecc1aef35f550ee3
dashboard link: https://syzkaller.appspot.com/bug?extid=aed048f49c59eb997737
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+aed048...@syzkaller.appspotmail.com

BUG: using smp_processor_id() in preemptible [00000000] code: systemd-rfkill/6728
caller is ext4_mb_new_blocks+0xa4d/0x3b70 fs/ext4/mballoc.c:4711
CPU: 1 PID: 6728 Comm: systemd-rfkill Not tainted 5.7.0-next-20200602-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x18f/0x20d lib/dump_stack.c:118
check_preemption_disabled+0x20d/0x220 lib/smp_processor_id.c:48
ext4_mb_new_blocks+0xa4d/0x3b70 fs/ext4/mballoc.c:4711
ext4_ext_map_blocks+0x201b/0x33e0 fs/ext4/extents.c:4244
ext4_map_blocks+0x4cb/0x1640 fs/ext4/inode.c:626
ext4_getblk+0xad/0x520 fs/ext4/inode.c:833
ext4_bread+0x7c/0x380 fs/ext4/inode.c:883
ext4_append+0x153/0x360 fs/ext4/namei.c:67
ext4_init_new_dir fs/ext4/namei.c:2757 [inline]
ext4_mkdir+0x5e0/0xdf0 fs/ext4/namei.c:2802
vfs_mkdir+0x419/0x690 fs/namei.c:3632
do_mkdirat+0x21e/0x280 fs/namei.c:3655
do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f9ffaa79687
Code: Bad RIP value.
RSP: 002b:00007ffeb3197c38 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 000055c2e6155985 RCX: 00007f9ffaa79687
RDX: 00007ffeb3197b00 RSI: 00000000000001ed RDI: 000055c2e6155985
RBP: 00007f9ffaa79680 R08: 0000000000000100 R09: 0000000000000000
R10: 000055c2e6155980 R11: 0000000000000246 R12: 00000000000001ed
R13: 00007ffeb3197dc0 R14: 0000000000000000 R15: 0000000000000000

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Eric Biggers

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Jun 5, 2020, 12:02:23 AM6/5/20

to Ritesh Harjani, adilger...@dilger.ca, linux...@vger.kernel.org, linux-...@vger.kernel.org, linux...@vger.kernel.org, s...@canb.auug.org.au, syzkall...@googlegroups.com, ty...@mit.edu, syzbot

Introduced by:

commit 42f56b7a4a7db127a9d281da584152dc3d525d25
Author: Ritesh Harjani <rit...@linux.ibm.com>
Date: Wed May 20 12:10:34 2020 +0530

ext4: mballoc: introduce pcpu seqcnt for freeing PA to improve ENOSPC handling

Eric Biggers

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Jun 5, 2020, 12:12:21 AM6/5/20

to Ritesh Harjani, adilger...@dilger.ca, linux...@vger.kernel.org, linux-...@vger.kernel.org, linux...@vger.kernel.org, s...@canb.auug.org.au, syzkall...@googlegroups.com, ty...@mit.edu, syzbot

On Thu, Jun 04, 2020 at 09:02:20PM -0700, Eric Biggers wrote:
> Introduced by:
>
> commit 42f56b7a4a7db127a9d281da584152dc3d525d25
> Author: Ritesh Harjani <rit...@linux.ibm.com>
> Date: Wed May 20 12:10:34 2020 +0530
>
> ext4: mballoc: introduce pcpu seqcnt for freeing PA to improve ENOSPC handling
>

Hmm, syzbot reported this several times already. Marking it as a duplicate
of the report where the discussion happened:

#syz dup: linux-next test error: BUG: using smp_processor_id() in preemptible [ADDR] code: syz-fuzzer/6792

- Eric

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