On Wed, Mar 03, 2021 at 04:37:18PM +0100, Michel Dänzer wrote: > On 2021-02-22 10:15 a.m., syzbot wrote: > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: 29ad81a1 arch/x86: add missing include to sparsemem.h > > git tree: https://github.com/google/kmsan.git master > > console output: https://syzkaller.appspot.com/x/log.txt?x=111e6312d00000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=c8e3b38ca92283e > > dashboard link: https://syzkaller.appspot.com/bug?extid=620cf21140fc7e772a5d > > compiler: Debian clang version 11.0.1-2 > > userspace arch: i386 > > > > Unfortunately, I don't have any reproducer for this issue yet. > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+620cf21140fc7e772a5d@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > ===================================================== > > BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 > > CPU: 1 PID: 26999 Comm: syz-executor.2 Not tainted 5.11.0-rc7-syzkaller #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > Call Trace: > > __dump_stack lib/dump_stack.c:79 [inline] > > dump_stack+0x21c/0x280 lib/dump_stack.c:120 > > kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118 > > kmsan_internal_check_memory+0x484/0x520 mm/kmsan/kmsan.c:437 > > kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 > > instrument_copy_to_user include/linux/instrumented.h:121 [inline] > > _copy_to_user+0x1ac/0x270 lib/usercopy.c:33 > > copy_to_user include/linux/uaccess.h:209 [inline] > > compat_drm_wait_vblank+0x36f/0x450 drivers/gpu/drm/drm_ioc32.c:866 > > drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995 > > __do_compat_sys_ioctl fs/ioctl.c:842 [inline] > > __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793 > > __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793 > > do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline] > > __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141 > > do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166 > > do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209 > > entry_SYSENTER_compat_after_hwframe+0x4d/0x5c > > RIP: 0023:0xf7f47549 > > Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 > > RSP: 002b:00000000f55415fc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 > > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000c018643a > > RDX: 0000000020000100 RSI: 0000000000000000 RDI: 0000000000000000 > > RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 > > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 > > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > > > > Uninit was stored to memory at: > > kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline] > > kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:289 > > __msan_chain_origin+0x57/0xa0 mm/kmsan/kmsan_instr.c:147 > > compat_drm_wait_vblank+0x43c/0x450 drivers/gpu/drm/drm_ioc32.c:865 > > drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995 > > __do_compat_sys_ioctl fs/ioctl.c:842 [inline] > > __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793 > > __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793 > > do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline] > > __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141 > > do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166 > > do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209 > > entry_SYSENTER_compat_after_hwframe+0x4d/0x5c > > > > Local variable ----req@compat_drm_wait_vblank created at: > > compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849 > > compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849 > > > > Bytes 12-15 of 16 are uninitialized > > Memory access of size 16 starts at ffff88814ffe3c98 > > Data copied to user address 0000000020000100 > > ===================================================== > > compat_drm_wait_vblank would need to initialize > > req.reply.tval_usec = req32.reply.tval_usec; > > before calling drm_ioctl_kernel, since it's not aliased by any > req.request.* member, and drm_wait_vblank_ioctl doesn't always write to > it. I've fixed this in commit e926c474ebee404441c838d18224cd6f246a71b7 Author: Daniel Vetter <daniel.vetter@xxxxxxxx> Date: Mon Feb 22 11:06:43 2021 +0100 drm/compat: Clear bounce structures Or at least tried to. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
