================================================================== BUG: KASAN: vmalloc-out-of-bounds in fb_write_offset drivers/video/fbdev/core/sysmem.h:30 [inline] BUG: KASAN: vmalloc-out-of-bounds in bitfill drivers/video/fbdev/core/fb_fillrect.h:133 [inline] BUG: KASAN: vmalloc-out-of-bounds in fb_fillrect_static drivers/video/fbdev/core/fb_fillrect.h:219 [inline] BUG: KASAN: vmalloc-out-of-bounds in fb_fillrect drivers/video/fbdev/core/fb_fillrect.h:278 [inline] BUG: KASAN: vmalloc-out-of-bounds in sys_fillrect+0x174a/0x1910 drivers/video/fbdev/core/sysfillrect.c:24 Write of size 8 at addr ffffc90004d59000 by task syz.3.14305/3055 CPU: 1 UID: 0 PID: 3055 Comm: syz.3.14305 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1a0 mm/kasan/report.c:595 fb_write_offset drivers/video/fbdev/core/sysmem.h:30 [inline] bitfill drivers/video/fbdev/core/fb_fillrect.h:133 [inline] fb_fillrect_static drivers/video/fbdev/core/fb_fillrect.h:219 [inline] fb_fillrect drivers/video/fbdev/core/fb_fillrect.h:278 [inline] sys_fillrect+0x174a/0x1910 drivers/video/fbdev/core/sysfillrect.c:24 drm_fbdev_shmem_defio_fillrect+0x22/0x140 drivers/gpu/drm/drm_fbdev_shmem.c:39 bit_clear+0x17d/0x220 drivers/video/fbdev/core/bitblit.c:73 __fbcon_clear+0x633/0x760 drivers/video/fbdev/core/fbcon.c:1326 fbcon_scroll+0x48b/0x650 drivers/video/fbdev/core/fbcon.c:1886 con_scroll+0x464/0x690 drivers/tty/vt/vt.c:588 csi_M drivers/tty/vt/vt.c:2140 [inline] csi_ECMA drivers/tty/vt/vt.c:2559 [inline] do_con_trol drivers/tty/vt/vt.c:2733 [inline] do_con_write+0x6888/0x8550 drivers/tty/vt/vt.c:3228 con_write+0x23/0xb0 drivers/tty/vt/vt.c:3565 process_output_block drivers/tty/n_tty.c:557 [inline] n_tty_write+0x44f/0x12d0 drivers/tty/n_tty.c:2366 iterate_tty_write drivers/tty/tty_io.c:1006 [inline] file_tty_write.isra.0+0x4d2/0x890 drivers/tty/tty_io.c:1081 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:688 ksys_write+0x12a/0x250 fs/read_write.c:740 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe3/0x8c0 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7fb8f6c Code: d2 74 05 c1 e8 0c 89 02 8b 5d fc 31 c0 c9 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 58 b8 77 00 00 00 cd 80 0f 0b 8d b6 00 00 00 00 b8 ad RSP: 002b:00000000f547650c EFLAGS: 00000292 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000080001040 RDX: 0000000000001006 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 The buggy address belongs to a 0-page vmalloc region starting at 0xffffc90004a59000 allocated at drm_gem_shmem_vmap_locked+0x54b/0x800 drivers/gpu/drm/drm_gem_shmem_helper.c:411 Memory state around the buggy address: ffffc90004d58f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc90004d58f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffffc90004d59000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffffc90004d59080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90004d59100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ================================================================== ---------------- Code disassembly (best guess): 0: d2 74 05 c1 shlb %cl,-0x3f(%rbp,%rax,1) 4: e8 0c 89 02 8b call 0x8b028915 9: 5d pop %rbp a: fc cld b: 31 c0 xor %eax,%eax d: c9 leave e: c3 ret f: 90 nop 10: 90 nop 11: 90 nop 12: 90 nop 13: 90 nop 14: 90 nop 15: 90 nop 16: 90 nop 17: 90 nop 18: 90 nop 19: 90 nop 1a: 90 nop 1b: 90 nop 1c: 90 nop 1d: 90 nop 1e: 0f 1f 00 nopl (%rax) 21: 51 push %rcx 22: 52 push %rdx 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 ret 2e: 58 pop %rax 2f: b8 77 00 00 00 mov $0x77,%eax 34: cd 80 int $0x80 36: 0f 0b ud2 38: 8d b6 00 00 00 00 lea 0x0(%rsi),%esi 3e: b8 .byte 0xb8 3f: ad lods %ds:(%rsi),%eax