On Sat, Nov 26, 2016 at 6:35 PM, David Herrmann <dh.herrmann@xxxxxxxxx> wrote: > Hi > > On Sat, Nov 26, 2016 at 6:17 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: >> On Fri, Sep 9, 2016 at 1:56 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: >>> Hello, >>> >>> The following program triggers GPF in drm_getcap: >>> >>> // autogenerated by syzkaller (http://github.com/google/syzkaller) >>> #include <fcntl.h> >>> #include <stddef.h> >>> #include <stdint.h> >>> #include <sys/ioctl.h> >>> #include <sys/stat.h> >>> #include <sys/syscall.h> >>> #include <sys/types.h> >>> #include <unistd.h> >>> >>> int main() >>> { >>> int fd = open("/dev/dri/card0", O_RDONLY); >>> uint64_t data[2] = {0x11, 0x80}; >>> ioctl(fd, 0xc010640cul /*DRM_IOCTL_GET_CAP*/, data); >>> return 0; >>> } >>> >>> >>> general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN >>> Modules linked in: >>> CPU: 1 PID: 5745 Comm: syz-executor Not tainted 4.8.0-rc5-next-20160905+ #14 >>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 >>> task: ffff8800310dc540 task.stack: ffff88003cbc0000 >>> RIP: 0010:[<ffffffff834ca87b>] [<ffffffff834ca87b>] >>> drm_getcap+0x34b/0x4f0 drivers/gpu/drm/drm_ioctl.c:260 >>> RSP: 0018:ffff88003cbc7c28 EFLAGS: 00010202 >>> RAX: 0000000000000058 RBX: ffff88003cbc7cf8 RCX: ffffc90001db0000 >>> RDX: 000000000000005d RSI: ffff88003cbc7cf8 RDI: 00000000000002c0 >>> RBP: ffff88003cbc7c50 R08: ffffed0007978fa1 R09: ffffed0007978fa0 >>> R10: ffff88003cbc7d07 R11: ffffed0007978fa1 R12: fffffffffffffff0 >>> R13: dffffc0000000000 R14: ffff88003bcc6850 R15: fffffffffffffff2 >>> FS: 00007fcbf4e03700(0000) GS:ffff88003ed00000(0000) knlGS:0000000000000000 >>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> CR2: 00000000006dce00 CR3: 0000000066135000 CR4: 00000000000006e0 >>> DR0: 000000000000001e DR1: 000000000000001e DR2: 0000000000000000 >>> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 >>> Stack: >>> ffff88003c26db00 ffff88003cbc7cf8 ffffffff875a3000 ffffffff88cf0ee0 >>> fffffffffffffff2 ffff88003cbc7dc0 ffffffff834cb57c 000000000000e200 >>> 1ffff10000000001 ffffffff875a1ba0 ffffffff882ae930 0000000000000010 >>> Call Trace: >>> [<ffffffff834cb57c>] drm_ioctl+0x54c/0xaf0 drivers/gpu/drm/drm_ioctl.c:728 >>> [< inline >] vfs_ioctl fs/ioctl.c:43 >>> [<ffffffff818a331c>] do_vfs_ioctl+0x18c/0x1080 fs/ioctl.c:675 >>> [< inline >] SYSC_ioctl fs/ioctl.c:690 >>> [<ffffffff818a429f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:681 >>> [<ffffffff86e1a8c0>] entry_SYSCALL_64_fastpath+0x23/0xc1 >>> Code: 3c 28 00 0f 85 88 01 00 00 49 8b 44 24 10 49 39 c6 4c 8d 60 f0 >>> 74 82 e8 64 19 10 fe 49 8d bc 24 d0 02 00 00 48 89 f8 48 c1 e8 03 <42> >>> 80 3c 28 00 0f 85 6f 01 00 00 4d 8b bc 24 d0 02 00 00 49 8d >>> RIP [<ffffffff834ca87b>] drm_getcap+0x34b/0x4f0 drivers/gpu/drm/drm_ioctl.c:260 >>> RSP <ffff88003cbc7c28> >>> ---[ end trace c6e1afa8cd73b880 ]--- >>> >>> >>> On commit 4affa544adb8077403893e62b9e327fcf87de6f7 (Sep 8) of linux-next. >> >> ping >> >> Still happens on 16ae16c6e5616c084168740990fc508bda6655d4 (Nov 24). > > I suspect this is because we run drm_for_each_crtc() in > drm_getcap(DRM_PAGE_FLIP_TARGET) on a legacy driver (meaning > mode_config is not initialized). @danvet, how about always > initializing mode_config to 0/empty/dummy? > > Dmitry, what driver do you run this on? And is CONFIG_DRM_LEGACY enabled? CONFIG_DRM_LEGACY is enabled. How can I understand what driver is used? This happens inside of qemu. This is the device: crw-rw---T 1 root video 226, 0 Nov 26 17:45 /dev/dri/card0 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
