================================================================== 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+0x1560/0x1d10 drivers/video/fbdev/core/sysimgblt.c:323 Write of size 4 at addr ffff800025959fc0 by task syz.3.547/6638 CPU: 0 PID: 6638 Comm: syz.3.547 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026 Call trace: dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 print_address_description+0x88/0x218 mm/kasan/report.c:316 print_report+0x50/0x68 mm/kasan/report.c:420 kasan_report+0xa8/0xfc mm/kasan/report.c:524 __asan_report_store4_noabort+0x2c/0x38 mm/kasan/report_generic.c:355 fast_imageblit drivers/video/fbdev/core/sysimgblt.c:257 [inline] sys_imageblit+0x1560/0x1d10 drivers/video/fbdev/core/sysimgblt.c:323 drm_fb_helper_sys_imageblit+0x40/0x464 drivers/gpu/drm/drm_fb_helper.c:864 drm_fbdev_fb_imageblit+0x170/0x1dc drivers/gpu/drm/drm_fb_helper.c:2402 cw_putcs_aligned drivers/video/fbdev/core/fbcon_cw.c:110 [inline] cw_putcs+0xab0/0xd18 drivers/video/fbdev/core/fbcon_cw.c:158 fbcon_putcs+0x30c/0x4b8 drivers/video/fbdev/core/fbcon.c:1299 do_update_region+0x40c/0x554 drivers/tty/vt/vt.c:676 redraw_screen+0x78c/0xcc0 drivers/tty/vt/vt.c:1035 vc_do_resize+0xc98/0x1154 drivers/tty/vt/vt.c:1344 vc_resize+0x58/0x6c drivers/tty/vt/vt.c:1364 vt_resizex+0x3e8/0x5d8 drivers/tty/vt/vt_ioctl.c:720 vt_ioctl+0xc78/0x1ff0 drivers/tty/vt/vt_ioctl.c:941 tty_ioctl+0x8a4/0xde4 drivers/tty/tty_io.c:2793 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:589 The buggy address belongs to a vmalloc virtual mapping Memory state around the buggy address: ffff800025959e80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffff800025959f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 >ffff800025959f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffff80002595a000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffff80002595a080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ================================================================== Unable to handle kernel paging request at virtual address ffff800025959fc0 KASAN: probably user-memory-access in range [0x000000012cacfe00-0x000000012cacfe07] Mem abort info: ESR = 0x0000000096000047 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x07: level 3 translation fault Data abort info: ISV = 0, ISS = 0x00000047 CM = 0, WnR = 1 swapper pgtable: 4k pages, 48-bit VAs, pgdp=000000020bb8e000 [ffff800025959fc0] pgd=100000023ffff003, p4d=100000023ffff003, pud=100000023fffe003, pmd=100000010e7f6003, pte=0000000000000000 Internal error: Oops: 0000000096000047 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 6638 Comm: syz.3.547 Tainted: G B syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026 pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--) pc : fast_imageblit drivers/video/fbdev/core/sysimgblt.c:257 [inline] pc : sys_imageblit+0x1338/0x1d10 drivers/video/fbdev/core/sysimgblt.c:323 lr : fast_imageblit drivers/video/fbdev/core/sysimgblt.c:257 [inline] lr : sys_imageblit+0x1560/0x1d10 drivers/video/fbdev/core/sysimgblt.c:323 sp : ffff800022bf7100 x29: ffff800022bf7250 x28: 0000000000000001 x27: ffff800025959fc0 x26: ffff0000ce591bf1 x25: 1fffe00019cb237e x24: ffff800025959fc0 x23: ffff800025959fc0 x22: 0000000000000000 x21: ffff800022bf71c0 x20: 0000000000000000 x19: ffff0000ce591bf0 x18: 1fffe00033c2177e x17: 3d3d3d3d3d3d3d3d x16: ffff800011ba16d0 x15: 0000000000000002 x14: 0000000000000001 x13: 1ffff000031fab68 x12: 0000000000080000 x11: dfff800000000000 x10: ffff80002942c000 x9 : 0000000000000000 x8 : ffff0000d3be3800 x7 : 64206b636f6c2067 x6 : ffff8000083151e4 x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff800008196234 x2 : 0000000000000001 x1 : 0000000000000000 x0 : ffff800025959fc0 Call trace: fast_imageblit drivers/video/fbdev/core/sysimgblt.c:257 [inline] sys_imageblit+0x1338/0x1d10 drivers/video/fbdev/core/sysimgblt.c:323 drm_fb_helper_sys_imageblit+0x40/0x464 drivers/gpu/drm/drm_fb_helper.c:864 drm_fbdev_fb_imageblit+0x170/0x1dc drivers/gpu/drm/drm_fb_helper.c:2402 cw_putcs_aligned drivers/video/fbdev/core/fbcon_cw.c:110 [inline] cw_putcs+0xab0/0xd18 drivers/video/fbdev/core/fbcon_cw.c:158 fbcon_putcs+0x30c/0x4b8 drivers/video/fbdev/core/fbcon.c:1299 do_update_region+0x40c/0x554 drivers/tty/vt/vt.c:676 redraw_screen+0x78c/0xcc0 drivers/tty/vt/vt.c:1035 vc_do_resize+0xc98/0x1154 drivers/tty/vt/vt.c:1344 vc_resize+0x58/0x6c drivers/tty/vt/vt.c:1364 vt_resizex+0x3e8/0x5d8 drivers/tty/vt/vt_ioctl.c:720 vt_ioctl+0xc78/0x1ff0 drivers/tty/vt/vt_ioctl.c:941 tty_ioctl+0x8a4/0xde4 drivers/tty/tty_io.c:2793 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:589 Code: 38eb6928 b86a5ab4 350010c8 8b160360 (b8004414) ---[ end trace 0000000000000000 ]--- ---------------- Code disassembly (best guess): 0: 38eb6928 ldrsb w8, [x9, x11] 4: b86a5ab4 ldr w20, [x21, w10, uxtw #2] 8: 350010c8 cbnz w8, 0x220 c: 8b160360 add x0, x27, x22 * 10: b8004414 str w20, [x0], #4 <-- trapping instruction