syzbot has found a reproducer for the following issue on: HEAD commit: c7fb1692dc01 Merge tag 'for-linus' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11742d63980000 kernel config: https://syzkaller.appspot.com/x/.config?x=660f6eb11f9c7dc5 dashboard link: https://syzkaller.appspot.com/bug?extid=c4b7aa0513823e2ea880 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11703653980000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=154565b7980000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-c7fb1692.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/246da487db6f/vmlinux-c7fb1692.xz kernel image: https://storage.googleapis.com/syzbot-assets/f0ea1e4dac0f/bzImage-c7fb1692.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+c4b7aa0513823e2ea880@xxxxxxxxxxxxxxxxxxxxxxxxx R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000001 R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001 </TASK> ================================================================== BUG: KASAN: vmalloc-out-of-bounds in fast_imageblit drivers/video/fbdev/core/sysimgblt.c:257 [inline] BUG: KASAN: vmalloc-out-of-bounds in sys_imageblit+0x1ec6/0x2b00 drivers/video/fbdev/core/sysimgblt.c:326 Write of size 4 at addr ffffc90001c41000 by task syz-executor161/5103 CPU: 0 UID: 0 PID: 5103 Comm: syz-executor161 Not tainted 6.11.0-rc6-syzkaller-00048-gc7fb1692dc01 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 fast_imageblit drivers/video/fbdev/core/sysimgblt.c:257 [inline] sys_imageblit+0x1ec6/0x2b00 drivers/video/fbdev/core/sysimgblt.c:326 drm_fbdev_shmem_defio_imageblit+0x2e/0x100 drivers/gpu/drm/drm_fbdev_shmem.c:39 bit_putcs+0x18ba/0x1db0 fbcon_putcs+0x255/0x390 drivers/video/fbdev/core/fbcon.c:1288 do_update_region+0x396/0x450 drivers/tty/vt/vt.c:619 redraw_screen+0x902/0xe90 drivers/tty/vt/vt.c:971 con2fb_init_display drivers/video/fbdev/core/fbcon.c:794 [inline] set_con2fb_map+0xa6c/0x10a0 drivers/video/fbdev/core/fbcon.c:865 fbcon_set_con2fb_map_ioctl+0x207/0x320 drivers/video/fbdev/core/fbcon.c:3092 do_fb_ioctl+0x38f/0x7b0 drivers/video/fbdev/core/fb_chrdev.c:138 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7feb9b353729 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 a1 1a 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffde9b9f968 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffde9b9f980 RCX: 00007feb9b353729 RDX: 00000000200000c0 RSI: 0000000000004610 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffde9b9f707 R09: 00000000000000a0 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000001 R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001 </TASK> The buggy address belongs to the virtual mapping at [ffffc90001941000, ffffc90001c42000) created by: drm_gem_shmem_vmap+0x3ac/0x630 drivers/gpu/drm/drm_gem_shmem_helper.c:343 Memory state around the buggy address: ffffc90001c40f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc90001c40f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffffc90001c41000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffffc90001c41080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90001c41100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ================================================================== --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.
