BUG: unable to handle kernel NULL pointer dereference in bpf_prog_ADDR_L

syzbot
2020-07-06T06:21:29Z

Hello,

syzbot found the following crash on:

HEAD commit: cb8e59cc Merge git://git.kernel.org/pub/scm/linux/kernel/g..
git tree: bpf-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1446cfd3100000
kernel config: https://syzkaller.appspot.com/x/.config?x=a16ddbc78955e3a9
dashboard link: https://syzkaller.appspot.com/bug?extid=a4c6e533af740abd3922
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+a4c6e533af740abd3922@syzkaller.appspotmail.com

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 85748067 P4D 85748067 PUD 61918067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 4768 Comm: syz-executor.0 Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:bpf_prog_6df1c5236f32720a_L+0x1f/0xa18
Code: cc cc cc cc cc cc cc cc cc cc cc 0f 1f 44 00 00 55 48 89 e5 48 81 ec 00 00 00 00 53 41 55 41 56 41 57 6a 00 31 c0 48 8b 7f 28 <48> 8b 7f 00 8b bf 00 01 00 00 5b 41 5f 41 5e 41 5d 5b c9 c3 cc cc
RSP: 0018:ffffc90001ee7ac0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffffc900022ea000
RDX: 0000000000000230 RSI: ffffc90000cb8038 RDI: 0000000000000000
RBP: ffffc90001ee7ae8 R08: ffff88805dc5e200 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90000cb8000
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff88805dc5e200
FS: 00007fc83e30f700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000008c0f4000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
bpf_prog_run_xdp include/linux/filter.h:734 [inline]
bpf_test_run+0x226/0xc70 net/bpf/test_run.c:47
bpf_prog_test_run_xdp+0x2ca/0x510 net/bpf/test_run.c:507
bpf_prog_test_run kernel/bpf/syscall.c:2998 [inline]
__do_sys_bpf+0x28ce/0x4a80 kernel/bpf/syscall.c:4138
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45cb29
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc83e30ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00000000004dade0 RCX: 000000000045cb29
RDX: 0000000000000040 RSI: 0000000020000040 RDI: 000000000000000a
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000005d R14: 00000000004c32db R15: 00007fc83e30f6d4
Modules linked in:
CR2: 0000000000000000
---[ end trace 6c5d2c7e681a670d ]---
RIP: 0010:bpf_prog_6df1c5236f32720a_L+0x1f/0xa18
Code: cc cc cc cc cc cc cc cc cc cc cc 0f 1f 44 00 00 55 48 89 e5 48 81 ec 00 00 00 00 53 41 55 41 56 41 57 6a 00 31 c0 48 8b 7f 28 <48> 8b 7f 00 8b bf 00 01 00 00 5b 41 5f 41 5e 41 5d 5b c9 c3 cc cc
RSP: 0018:ffffc90001ee7ac0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffffc900022ea000
RDX: 0000000000000230 RSI: ffffc90000cb8038 RDI: 0000000000000000
RBP: ffffc90001ee7ae8 R08: ffff88805dc5e200 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90000cb8000
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff88805dc5e200
FS: 00007fc83e30f700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000008c0f4000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600

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