Re: WARNING in bpf_jit_free

From: syzbot <syzbot+2ff1e7cb738fd3c41113@syzkaller.appspotmail.com>
To: airlied@linux.ie, ast@kernel.org, bpf@vger.kernel.org,
	daniel@ffwll.ch,  daniel@iogearbox.net, davem@davemloft.net,
	dri-devel@lists.freedesktop.org,  hawk@kernel.org,
	jakub.kicinski@netronome.com, john.fastabend@gmail.com,
	 kafai@fb.com, linux-arm-kernel@lists.infradead.org,
	 linux-kernel@vger.kernel.org, maxime.ripard@bootlin.com,
	 netdev@vger.kernel.org, paul.kocialkowski@bootlin.com,
	songliubraving@fb.com,  syzkaller-bugs@googlegroups.com,
	wens@csie.org, xdp-newbies@vger.kernel.org,  yhs@fb.com
Subject: Re: WARNING in bpf_jit_free
Date: Sat, 08 Jun 2019 04:22:06 -0700	[thread overview]
Message-ID: <000000000000381684058ace28e5@google.com> (raw)
In-Reply-To: <000000000000e92d1805711f5552@google.com>

syzbot has found a reproducer for the following crash on:

HEAD commit:    79c3ba32 Merge tag 'drm-fixes-2019-06-07-1' of git://anong..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1201b971a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=60564cb52ab29d5b
dashboard link: https://syzkaller.appspot.com/bug?extid=2ff1e7cb738fd3c41113
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14a3bf51a00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=120d19f2a00000

The bug was bisected to:

commit 0fff724a33917ac581b5825375d0b57affedee76
Author: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Date:   Fri Jan 18 14:51:13 2019 +0000

     drm/sun4i: backend: Use explicit fourcc helpers for packed YUV422 check

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1467550f200000
final crash:    https://syzkaller.appspot.com/x/report.txt?x=1667550f200000
console output: https://syzkaller.appspot.com/x/log.txt?x=1267550f200000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2ff1e7cb738fd3c41113@syzkaller.appspotmail.com
Fixes: 0fff724a3391 ("drm/sun4i: backend: Use explicit fourcc helpers for  
packed YUV422 check")

WARNING: CPU: 0 PID: 8951 at kernel/bpf/core.c:851 bpf_jit_free+0x157/0x1b0
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 8951 Comm: kworker/0:0 Not tainted 5.2.0-rc3+ #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: events bpf_prog_free_deferred
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x172/0x1f0 lib/dump_stack.c:113
  panic+0x2cb/0x744 kernel/panic.c:219
  __warn.cold+0x20/0x4d kernel/panic.c:576
  report_bug+0x263/0x2b0 lib/bug.c:186
  fixup_bug arch/x86/kernel/traps.c:179 [inline]
  fixup_bug arch/x86/kernel/traps.c:174 [inline]
  do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
  do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
  invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:986
RIP: 0010:bpf_jit_free+0x157/0x1b0
Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 5d 48 b8 00 02 00 00  
00 00 ad de 48 39 43 70 0f 84 05 ff ff ff e8 f9 b5 f4 ff <0f> 0b e9 f9 fe  
ff ff e8 bd 53 2d 00 e9 d9 fe ff ff 48 89 7d e0 e8
RSP: 0018:ffff88808886fcb0 EFLAGS: 00010293
RAX: ffff88808cb6c480 RBX: ffff88809051d280 RCX: ffffffff817ae68d
RDX: 0000000000000000 RSI: ffffffff817bf0f7 RDI: ffff88809051d2f0
RBP: ffff88808886fcd0 R08: 1ffffffff14ccaa8 R09: fffffbfff14ccaa9
R10: fffffbfff14ccaa8 R11: ffffffff8a665547 R12: ffffc90001925000
R13: ffff88809051d2e8 R14: ffff8880a0e43900 R15: ffff8880ae834840
  bpf_prog_free_deferred+0x27a/0x350 kernel/bpf/core.c:1984
  process_one_work+0x989/0x1790 kernel/workqueue.c:2269
  worker_thread+0x98/0xe40 kernel/workqueue.c:2415
  kthread+0x354/0x420 kernel/kthread.c:255
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..

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