On Fri, Jan 31, 2020 at 11:28 PM syzbot <syzbot+0dc4444774d419e916c8@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: 39bed42d Merge tag 'for-linus-hmm' of git://git.kernel.org.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=179465bee00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=2646535f8818ae25 > 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=16251279e00000 > > The bug was bisected to: > > commit 7611750784664db46d0db95631e322aeb263dde7 > Author: Alex Deucher <alexander.deucher@xxxxxxx> > 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@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 761175078466 ("drm/amdgpu: use kernel is_power_of_2 rather than local version") Aside: This bisect line is complete nonsense ... I'm kinda at the point where I'm assuming that syzbot bisect results are garbage, which is maybe not what we want. I guess much stricter filtering for noise is needed, dunno. -Danile > > ================================================================== > 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 ffff88809fa67908 by task syz-executor.0/14871 > > CPU: 0 PID: 14871 Comm: syz-executor.0 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:639 > __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: 0033:0x45b349 > Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f871af46c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007f871af476d4 RCX: 000000000045b349 > RDX: 0000000020000180 RSI: 00000000c02064b2 RDI: 0000000000000003 > RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 0000000000000285 R14: 00000000004d14d0 R15: 000000000075bf2c > > Allocated by task 14871: > save_stack+0x23/0x90 mm/kasan/common.c:72 > set_track mm/kasan/common.c:80 [inline] > __kasan_kmalloc mm/kasan/common.c:513 [inline] > __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486 > kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527 > 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 14871: > 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:335 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474 > kasan_slab_free+0xe/0x10 mm/kasan/common.c:483 > __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 ffff88809fa67800 > which belongs to the cache kmalloc-1k of size 1024 > The buggy address is located 264 bytes inside of > 1024-byte region [ffff88809fa67800, ffff88809fa67c00) > The buggy address belongs to the page: > page:ffffea00027e99c0 refcount:1 mapcount:0 mapping:ffff8880aa400c40 index:0x0 > raw: 00fffe0000000200 ffffea0002293548 ffffea00023e1f08 ffff8880aa400c40 > raw: 0000000000000000 ffff88809fa67000 0000000100000002 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff88809fa67800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88809fa67880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > >ffff88809fa67900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff88809fa67980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88809fa67a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
