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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+0x1bac/0x25d0 drivers/video/fbdev/core/sysimgblt.c:323
Write of size 4 at addr ffffc90003cc9f80 by task syz.2.1014/8636

CPU: 1 PID: 8636 Comm: syz.2.1014 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 fast_imageblit drivers/video/fbdev/core/sysimgblt.c:257 [inline]
 sys_imageblit+0x1bac/0x25d0 drivers/video/fbdev/core/sysimgblt.c:323
 drm_fbdev_generic_defio_imageblit+0x2c/0x110 drivers/gpu/drm/drm_fbdev_generic.c:37
 cw_putcs_aligned drivers/video/fbdev/core/fbcon_cw.c:110 [inline]
 cw_putcs+0x15f3/0x18a0 drivers/video/fbdev/core/fbcon_cw.c:158
 fbcon_putcs+0x35c/0x520 drivers/video/fbdev/core/fbcon.c:1301
 do_update_region+0x4e9/0x640 drivers/tty/vt/vt.c:623
 invert_screen+0x8e2/0xa70 drivers/tty/vt/vt.c:748
 highlight drivers/tty/vt/selection.c:57 [inline]
 clear_selection+0x59/0x70 drivers/tty/vt/selection.c:85
 vc_do_resize+0x6f2/0x17f0 drivers/tty/vt/vt.c:1206
 fbcon_modechanged+0x80d/0x12b0 drivers/video/fbdev/core/fbcon.c:2715
 fbcon_rotate drivers/video/fbdev/core/fbcon.c:228 [inline]
 store_rotate+0x32d/0x500 drivers/video/fbdev/core/fbcon.c:3238
 kernfs_fop_write_iter+0x3a4/0x520 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x474/0x9a0 fs/read_write.c:584
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5a01f9e559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5a001f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5a02225fa0 RCX: 00007f5a01f9e559
RDX: 0000000000000001 RSI: 0000200000000300 RDI: 0000000000000003
RBP: 00007f5a020358b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5a02226038 R14: 00007f5a02225fa0 R15: 00007fffd66fc658
 </TASK>

The buggy address belongs to a 0-page vmalloc region starting at 0xffffc90003cca000 allocated at drm_gem_shmem_vmap+0x3c4/0x650 drivers/gpu/drm/drm_gem_shmem_helper.c:340
Memory state around the buggy address:
 ffffc90003cc9e80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90003cc9f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90003cc9f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc90003cca000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90003cca080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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