From: syzbot <syzbot+0dc4444774d419e916c8@syzkaller.appspotmail.com>
To: airlied@linux.ie, alexander.deucher@amd.com,
amd-gfx@lists.freedesktop.org, chris@chris-wilson.co.uk,
christian.koenig@amd.com, dan.carpenter@oracle.com,
daniel@ffwll.ch, davem@davemloft.net,
dri-devel@lists.freedesktop.org, emil.velikov@collabora.com,
eric@anholt.net, hdanton@sina.com,
linaro-mm-sig-owner@lists.linaro.org,
linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org,
linux-media@vger.kernel.org, netdev@vger.kernel.org,
robdclark@chromium.org, seanpaul@chromium.org,
sumit.semwal@linaro.org, syzkaller-bugs@googlegroups.com
Subject: Re: KASAN: use-after-free Read in vgem_gem_dumb_create
Date: Sat, 01 Feb 2020 20:38:12 -0800 [thread overview]
Message-ID: <000000000000d42f3e059d905fe3@google.com> (raw)
In-Reply-To: <000000000000ae2f81059d7716b8@google.com>
syzbot has found a reproducer for the following crash on:
HEAD commit: 94f2630b Merge tag '5.6-rc-small-smb3-fix-for-stable' of g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11d6c776e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=99db4e42d047be3
dashboard link: https://syzkaller.appspot.com/bug?extid=0dc4444774d419e916c8
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=152385bee00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=123210a1e00000
The bug was bisected to:
commit 7611750784664db46d0db95631e322aeb263dde7
Author: Alex Deucher <alexander.deucher@amd.com>
Date: Wed Jun 21 16:31:41 2017 +0000
drm/amdgpu: use kernel is_power_of_2 rather than local version
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=11628df1e00000
final crash: https://syzkaller.appspot.com/x/report.txt?x=13628df1e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=15628df1e00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+0dc4444774d419e916c8@syzkaller.appspotmail.com
Fixes: 761175078466 ("drm/amdgpu: use kernel is_power_of_2 rather than local version")
==================================================================
BUG: KASAN: use-after-free in vgem_gem_dumb_create+0x238/0x250 drivers/gpu/drm/vgem/vgem_drv.c:221
Read of size 8 at addr ffff88809a2ee908 by task syz-executor815/10244
CPU: 1 PID: 10244 Comm: syz-executor815 Not tainted 5.5.0-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+0x197/0x210 lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
__kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506
kasan_report+0x12/0x20 mm/kasan/common.c:641
__asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
vgem_gem_dumb_create+0x238/0x250 drivers/gpu/drm/vgem/vgem_drv.c:221
drm_mode_create_dumb+0x282/0x310 drivers/gpu/drm/drm_dumb_buffers.c:94
drm_mode_create_dumb_ioctl+0x26/0x30 drivers/gpu/drm/drm_dumb_buffers.c:100
drm_ioctl_kernel+0x244/0x300 drivers/gpu/drm/drm_ioctl.c:786
drm_ioctl+0x54e/0xa60 drivers/gpu/drm/drm_ioctl.c:886
vfs_ioctl fs/ioctl.c:47 [inline]
ksys_ioctl+0x123/0x180 fs/ioctl.c:747
__do_sys_ioctl fs/ioctl.c:756 [inline]
__se_sys_ioctl fs/ioctl.c:754 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x44c3e9
Code: e8 8c e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 1b cc fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f40263e9db8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006ddc58 RCX: 000000000044c3e9
RDX: 0000000020000000 RSI: 00000000c02064b2 RDI: 0000000000000004
RBP: 00000000006ddc50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006ddc5c
R13: 00007ffed0d4362f R14: 00007f40263ea9c0 R15: 00000000006ddc5c
Allocated by task 10244:
save_stack+0x23/0x90 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
__kasan_kmalloc mm/kasan/common.c:515 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529
kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551
kmalloc include/linux/slab.h:556 [inline]
kzalloc include/linux/slab.h:670 [inline]
__vgem_gem_create+0x49/0x100 drivers/gpu/drm/vgem/vgem_drv.c:165
vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:194 [inline]
vgem_gem_dumb_create+0xd7/0x250 drivers/gpu/drm/vgem/vgem_drv.c:217
drm_mode_create_dumb+0x282/0x310 drivers/gpu/drm/drm_dumb_buffers.c:94
drm_mode_create_dumb_ioctl+0x26/0x30 drivers/gpu/drm/drm_dumb_buffers.c:100
drm_ioctl_kernel+0x244/0x300 drivers/gpu/drm/drm_ioctl.c:786
drm_ioctl+0x54e/0xa60 drivers/gpu/drm/drm_ioctl.c:886
vfs_ioctl fs/ioctl.c:47 [inline]
ksys_ioctl+0x123/0x180 fs/ioctl.c:747
__do_sys_ioctl fs/ioctl.c:756 [inline]
__se_sys_ioctl fs/ioctl.c:754 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 10244:
save_stack+0x23/0x90 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
kasan_set_free_info mm/kasan/common.c:337 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:476
kasan_slab_free+0xe/0x10 mm/kasan/common.c:485
__cache_free mm/slab.c:3426 [inline]
kfree+0x10a/0x2c0 mm/slab.c:3757
vgem_gem_free_object+0xbe/0xe0 drivers/gpu/drm/vgem/vgem_drv.c:68
drm_gem_object_free+0x100/0x220 drivers/gpu/drm/drm_gem.c:983
kref_put include/linux/kref.h:65 [inline]
drm_gem_object_put_unlocked drivers/gpu/drm/drm_gem.c:1017 [inline]
drm_gem_object_put_unlocked+0x196/0x1c0 drivers/gpu/drm/drm_gem.c:1002
vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:199 [inline]
vgem_gem_dumb_create+0x115/0x250 drivers/gpu/drm/vgem/vgem_drv.c:217
drm_mode_create_dumb+0x282/0x310 drivers/gpu/drm/drm_dumb_buffers.c:94
drm_mode_create_dumb_ioctl+0x26/0x30 drivers/gpu/drm/drm_dumb_buffers.c:100
drm_ioctl_kernel+0x244/0x300 drivers/gpu/drm/drm_ioctl.c:786
drm_ioctl+0x54e/0xa60 drivers/gpu/drm/drm_ioctl.c:886
vfs_ioctl fs/ioctl.c:47 [inline]
ksys_ioctl+0x123/0x180 fs/ioctl.c:747
__do_sys_ioctl fs/ioctl.c:756 [inline]
__se_sys_ioctl fs/ioctl.c:754 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The buggy address belongs to the object at ffff88809a2ee800
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 264 bytes inside of
1024-byte region [ffff88809a2ee800, ffff88809a2eec00)
The buggy address belongs to the page:
page:ffffea000268bb80 refcount:1 mapcount:0 mapping:ffff8880aa400c40 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002816448 ffffea0002551bc8 ffff8880aa400c40
raw: 0000000000000000 ffff88809a2ee000 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88809a2ee800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88809a2ee880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88809a2ee900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88809a2ee980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88809a2eea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
next prev parent reply other threads:[~2020-02-02 4:38 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-31 22:28 KASAN: use-after-free Read in vgem_gem_dumb_create syzbot
2020-02-01 5:56 ` Dan Carpenter
2020-02-02 4:38 ` syzbot [this message]
2020-02-02 13:19 ` Daniel Vetter
2020-02-03 9:06 ` Dan Carpenter
2020-02-03 15:08 ` Christian König
[not found] <20200201043209.13412-1-hdanton@sina.com>
2020-02-01 6:17 ` Dan Carpenter
[not found] ` <20200201090247.10928-1-hdanton@sina.com>
2020-02-01 16:25 ` Dan Carpenter
2020-02-02 13:17 ` Daniel Vetter
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