FYI, we noticed the following commit: commit 68ab21008a656abeb1fe2c7117a67eeab4d68ded ("mm: ovl: copy-up on MAP_SHARED") url: https://github.com/0day-ci/linux/commits/Miklos-Szeredi/overlayfs-fix-ro-rw-fd-data-inconsistecies/20161124-233654 base: https://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git overlayfs-next in testcase: trinity with following parameters: runtime: 300s test-description: Trinity is a linux system call fuzz tester. test-url: http://codemonkey.org.uk/projects/trinity/ on test machine: qemu-system-x86_64 -enable-kvm -cpu IvyBridge -m 360M caused below changes: +------------------------------------------+------------+------------+ | | b45dbaab96 | 68ab21008a | +------------------------------------------+------------+------------+ | boot_successes | 4 | 0 | | boot_failures | 0 | 5 | | BUG:unable_to_handle_kernel | 0 | 5 | | Oops | 0 | 5 | | RIP:vm_mmap_pgoff | 0 | 5 | | calltrace:SyS_mmap_pgoff | 0 | 5 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 5 | +------------------------------------------+------------+------------+ [ 5.829350] job=/lkp/scheduled/vm-ivb41-yocto-ia32-22/trinity-300s-yocto-tiny-i386-2016-04-22.cgz-68ab21008a656abeb1fe2c7117a67eeab4d68ded-20161126-104135-1r99nk0-0.yaml [ 5.829350] run-job /lkp/scheduled/vm-ivb41-yocto-ia32-22/trinity-300s-yocto-tiny-i386-2016-04-22.cgz-68ab21008a656abeb1fe2c7117a67eeab4d68ded-20161126-104135-1r99nk0-0.yaml [ 5.829350] /bin/busybox wget -q http://inn:80/~lkp/cgi-bin/lkp-jobfile-append-var?job_file=/lkp/scheduled/vm-ivb41-yocto-ia32-22/trinity-300s-yocto-tiny-i386-2016-04-22.cgz-68ab21008a656abeb1fe2c7117a67eeab4d68ded-20161126-104135-1r99nk0-0.yaml&job_state=running -O /dev/null [ 16.146778] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 [ 16.150092] IP: [] vm_mmap_pgoff+0x63/0xe7 [ 16.152858] PGD 71bf067 [ 16.153453] PUD 688b067 PMD 0 [ 16.154890] [ 16.156053] Oops: 0000 [#1] SMP [ 16.157251] Modules linked in: [ 16.158444] CPU: 0 PID: 1483 Comm: trinity Not tainted 4.9.0-rc4-00032-g68ab210 #1 [ 16.160691] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 16.162901] task: ffff880006cc1c00 task.stack: ffffc9000027c000 [ 16.164145] RIP: 0010:[] [] vm_mmap_pgoff+0x63/0xe7 [ 16.166525] RSP: 0000:ffffc9000027fe90 EFLAGS: 00010246 [ 16.167620] RAX: ffff880006cc1c00 RBX: 0000000000000000 RCX: 0000000000000001 [ 16.169186] RDX: 0000000000001000 RSI: 0000000000000000 RDI: 0000000000000000 [ 16.170761] RBP: ffffc9000027fed8 R08: 0000000000000021 R09: 0000000000000000 [ 16.172283] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 16.173878] R13: 0000000000001000 R14: ffff880006cc8800 R15: 0000000000000000 [ 16.175332] FS: 0000000000000000(0000) GS:ffff880016000000(0063) knlGS:0000000009af2840 [ 16.177455] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 16.178827] CR2: 0000000000000018 CR3: 00000000071b4000 CR4: 00000000001406f0 [ 16.180266] Stack: [ 16.181094] 0000000000000000 0000000000001000 0000000000000000 ffff880004b6ff00 [ 16.183365] 0000000000001000 0000000000000021 0000000000001000 0000000000000000 [ 16.185548] 0000000000000000 ffffc9000027ff30 ffffffff812036f8 0000000600270000 [ 16.187824] Call Trace: [ 16.188656] [] SyS_mmap_pgoff+0x184/0x1a9 [ 16.189918] [] do_int80_syscall_32+0x64/0xbf [ 16.191138] [] entry_INT80_compat+0x38/0x50 [ 16.192397] Code: 03 00 00 75 21 49 83 c6 68 4c 89 45 b8 49 c7 c5 fc ff ff ff 4c 89 f7 e8 c0 4c 8f 00 85 c0 4c 8b 45 b8 75 79 eb 37 f6 c1 02 75 da <48> 8b 47 18 8b 10 0f ba e2 1a 73 19 48 8b 48 60 4c 89 45 b8 ba [ 16.201562] RIP [] vm_mmap_pgoff+0x63/0xe7 [ 16.203254] RSP [ 16.204501] CR2: 0000000000000018 [ 16.206063] ---[ end trace 910d3120db07d449 ]--- [ 16.226016] Kernel panic - not syncing: Fatal exception [ 16.227115] Kernel Offset: disabled Elapsed time: 20 To reproduce: git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git cd lkp-tests bin/lkp qemu -k job-script # job-script is attached in this email Thanks, Kernel Test Robot