================================================================== BUG: KASAN: slab-out-of-bounds in fb_pad_unaligned_buffer+0x420/0x500 drivers/video/fbdev/core/fbmem.c:118 Read of size 1 at addr ffff88802fa7ab10 by task syz.1.2501/14099 CPU: 0 UID: 0 PID: 14099 Comm: syz.1.2501 Not tainted 6.16.0-rc3-next-20250627-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xd2/0x2b0 mm/kasan/report.c:521 kasan_report+0x118/0x150 mm/kasan/report.c:634 fb_pad_unaligned_buffer+0x420/0x500 drivers/video/fbdev/core/fbmem.c:118 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:129 [inline] bit_putcs+0x950/0x1a50 drivers/video/fbdev/core/bitblit.c:187 fbcon_putcs+0x3e2/0x5f0 drivers/video/fbdev/core/fbcon.c:1315 con_flush drivers/tty/vt/vt.c:2746 [inline] do_con_write+0x2835/0x5200 drivers/tty/vt/vt.c:3173 con_write+0x24/0x40 drivers/tty/vt/vt.c:3516 process_output_block drivers/tty/n_tty.c:561 [inline] n_tty_write+0xd32/0x11d0 drivers/tty/n_tty.c:2377 iterate_tty_write drivers/tty/tty_io.c:1006 [inline] file_tty_write+0x503/0x990 drivers/tty/tty_io.c:1081 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x54b/0xa90 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f400a38e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f400b29a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f400a5b6080 RCX: 00007f400a38e929 RDX: 0000000000001006 RSI: 0000200000001980 RDI: 000000000000000f RBP: 00007f400a410b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f400a5b6080 R15: 00007ffd02bf75e8 Allocated by task 6064: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4365 [inline] __kmalloc_noprof+0x27a/0x4f0 mm/slub.c:4377 kmalloc_noprof include/linux/slab.h:909 [inline] fbcon_set_font+0x519/0xe90 drivers/video/fbdev/core/fbcon.c:2523 con_font_set drivers/tty/vt/vt.c:4887 [inline] con_font_op+0xcac/0x1070 drivers/tty/vt/vt.c:4934 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:474 [inline] vt_ioctl+0x1a8a/0x1f00 drivers/tty/vt/vt_ioctl.c:751 tty_ioctl+0x929/0xde0 drivers/tty/tty_io.c:2792 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802fa7a800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 0 bytes to the right of allocated 784-byte region [ffff88802fa7a800, ffff88802fa7ab10) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2fa78 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801a841dc0 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801a841dc0 0000000000000000 dead000000000001 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0000be9e01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 44, tgid 44 (kworker/u8:3), ts 80808073972, free_ts 80664757748 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1848 prep_new_page mm/page_alloc.c:1856 [inline] get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3855 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5145 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419 alloc_slab_page mm/slub.c:2487 [inline] allocate_slab+0x8a/0x370 mm/slub.c:2655 new_slab mm/slub.c:2709 [inline] ___slab_alloc+0xbeb/0x1410 mm/slub.c:3891 __slab_alloc mm/slub.c:3981 [inline] __slab_alloc_node mm/slub.c:4056 [inline] slab_alloc_node mm/slub.c:4217 [inline] __do_kmalloc_node mm/slub.c:4364 [inline] __kmalloc_noprof+0x305/0x4f0 mm/slub.c:4377 kmalloc_noprof include/linux/slab.h:909 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] ieee802_11_parse_elems_full+0x152/0x2b20 net/mac80211/parse.c:1013 ieee802_11_parse_elems_crc net/mac80211/ieee80211_i.h:2418 [inline] ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2425 [inline] ieee80211_inform_bss+0x10c/0x10a0 net/mac80211/scan.c:79 rdev_inform_bss net/wireless/rdev-ops.h:418 [inline] cfg80211_inform_single_bss_data+0xd05/0x1ac0 net/wireless/scan.c:2367 cfg80211_inform_bss_data+0x1fb/0x3b20 net/wireless/scan.c:3222 cfg80211_inform_bss_frame_data+0x3d7/0x730 net/wireless/scan.c:3313 ieee80211_bss_info_update+0x746/0x9e0 net/mac80211/scan.c:226 ieee80211_rx_bss_info net/mac80211/ibss.c:1094 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1573 [inline] ieee80211_ibss_rx_queued_mgmt+0xa36/0x2ae0 net/mac80211/ibss.c:1600 ieee80211_iface_process_skb net/mac80211/iface.c:1668 [inline] ieee80211_iface_work+0x806/0xfe0 net/mac80211/iface.c:1722 cfg80211_wiphy_work+0x2df/0x460 net/wireless/core.c:435 page last free pid 6046 tgid 6046 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1392 [inline] __free_frozen_pages+0xb80/0xd80 mm/page_alloc.c:2892 discard_slab mm/slub.c:2753 [inline] __put_partials+0x156/0x1a0 mm/slub.c:3218 put_cpu_partial+0x17c/0x250 mm/slub.c:3293 __slab_free+0x2d5/0x3c0 mm/slub.c:4550 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4236 getname_flags+0xb8/0x540 fs/namei.c:146 getname include/linux/fs.h:2909 [inline] getname_maybe_null include/linux/fs.h:2916 [inline] vfs_fstatat+0x43/0x170 fs/stat.c:370 __do_sys_newfstatat fs/stat.c:542 [inline] __se_sys_newfstatat fs/stat.c:536 [inline] __x64_sys_newfstatat+0x116/0x190 fs/stat.c:536 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88802fa7aa00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88802fa7aa80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88802fa7ab00: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88802fa7ab80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802fa7ac00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================