From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f80.google.com (mail-oo1-f80.google.com [209.85.161.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DBCFB1A3029 for ; Wed, 10 Jun 2026 06:19:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781072374; cv=none; b=jn9GvHRVqZkLMrvcZQ2UzzUCoE1TzvKHGmZ6qZKsTS0IjZh5AUYzgs5dVsX2CD3HJZKRkpuH3RNrJfTxhjbzRGVOAhREEpGoGLPNtrpe4NfNRVYsFVf9gGsCByT0TckWiuXrnwkVbnpH9Y+ezWe9zAYILePe0jQ9pmS73E7MbSg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781072374; c=relaxed/simple; bh=5mo8GrRNGyZtOMeSeCGndEXpCO951pZFEgJHrUtxL0U=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=udDyot2T4l4haL4K8VI9FL4wBzsJQWusm4Wm14w+aYDYbEdl9WPDiMHLGFInHoKm7VWp2orO5pH2BFASbxAhJ1MoyXWhrg2rEOn5bDoN2XlIJjFbiEyf9QjvMtMuOsLU6UJc+KXYqffseqE55ZytH5PVlYx9nX50a2DqKTWI2rU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.80 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f80.google.com with SMTP id 006d021491bc7-69e87ffce0fso5187760eaf.1 for ; Tue, 09 Jun 2026 23:19:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781072372; x=1781677172; h=content-transfer-encoding:to:from:subject:message-id:date :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=zq6dIrNKFUl4fpnAHhFyrc9THsE98U1AyDAj4fNNJhY=; b=EIh0MjdWXi5ClR4HE5+GF/QOUV8XEhTod0gABSU7QX/+Y0jz6jZbyZf2Q3id5AKIid dvgM2AqPsUeAgOjV9aG50quS6X6udHvY91C9xKZD3WNDxnz2MZASyNE73lkVXimNwltd A+UWXSBQIQ0dE2Q/0HEF6Mm9MaAbDntKafDPOQ4YD4S3Zgj97CiOkzMbf5jCTTdDTSrO VE5ay8/IzA1PV/Q+KGG3E8M6EmeaCklM+FGGlMct/cl3KW5bpZYxuBWwkdmpHiJBcEOV zZCIseF3327xOQMybY3ueTrHADPowYh8W30MNbPKjMYOf8aHMAbUiu1ZOsKBgJpF5S2g zELw== X-Forwarded-Encrypted: i=1; AFNElJ/tyQ+TxrQV3oMV6Qm86vRNkKl9xaxFT0/1D+nFWnUIMD/ChGIQxaTa1WeZZCwnGE3e3X4Guzsm8wtz9g==@vger.kernel.org X-Gm-Message-State: AOJu0Yxp3UmPpMMVoLafgcyQrUsnSxhOabAJS9PWg2pLGM7Ohc0Xz/3v VgsjB2kj9JKd8vOOWEIx9ETm+Un++OW1Ao+i+8+CA3BjTn3y2/u4/twdjMnO5W8ohrS1FYUD+48 Nx9XpActE6df3KRhZ5TEUYYnmFQSKZBOXxml+Jpqkk8Gsnae71en7eHjDLTc= Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a4a:e64a:0:b0:694:96b2:9943 with SMTP id 006d021491bc7-69e68c20c2cmr11074425eaf.37.1781072372043; Tue, 09 Jun 2026 23:19:32 -0700 (PDT) Date: Tue, 09 Jun 2026 23:19:32 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a2901f4.39669fcc.33b062.00b4.GAE@google.com> Subject: [syzbot] [fbdev?] KASAN: slab-use-after-free Read in fb_mode_is_equal From: syzbot To: deller@gmx.de, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, simona@ffwll.ch, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hello, syzbot found the following issue on: HEAD commit: 9154c4af7829 Merge tag 'mmc-v7.1-rc3' of git://git.kernel..= . git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=3D16022bec580000 kernel config: https://syzkaller.appspot.com/x/.config?x=3D4e4d2284f2ffa41 dashboard link: https://syzkaller.appspot.com/bug?extid=3D81c7c6b52649fd072= 99d compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Deb= ian) 2.44 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/05514c1c6f79/disk-= 9154c4af.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/2a4514820c96/vmlinux-= 9154c4af.xz kernel image: https://storage.googleapis.com/syzbot-assets/a6cfe00f3884/bzI= mage-9154c4af.xz IMPORTANT: if you fix the issue, please add the following tag to the commit= : Reported-by: syzbot+81c7c6b52649fd07299d@syzkaller.appspotmail.com input: j=03J=07=C7=B8-=EF=BF=BD=EF=BF=BD=EF=BF=BD9=EF=BF=BD%v=EF=BF=BD=EF= =BF=BD=EF=BF=BDJ86=EF=BF=BD=1C=EF=BF=BD as /devices/virtual/input/input23 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D BUG: KASAN: slab-use-after-free in fb_mode_is_equal+0x280/0x2f0 drivers/vid= eo/fbdev/core/modedb.c:934 Read of size 4 at addr ffff88802666219c by task syz.6.4102/26504 CPU: 0 UID: 0 PID: 26504 Comm: syz.6.4102 Tainted: G L syz= kaller #0 PREEMPT(full)=20 Tainted: [L]=3DSOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Goo= gle 04/18/2026 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+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1d0 mm/kasan/report.c:595 fb_mode_is_equal+0x280/0x2f0 drivers/video/fbdev/core/modedb.c:934 fbcon_mode_deleted+0x146/0x1e0 drivers/video/fbdev/core/fbcon.c:2750 fb_set_var+0xe76/0x11b0 drivers/video/fbdev/core/fbmem.c:248 do_fb_ioctl+0x734/0x7e0 drivers/video/fbdev/core/fb_chrdev.c:90 fb_ioctl+0xe5/0x150 drivers/video/fbdev/core/fb_chrdev.c:169 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f828819ce59 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 f= f 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8285fb2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f8288416270 RCX: 00007f828819ce59 RDX: 0000200000000080 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 00007f8288232d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8288416308 R14: 00007f8288416270 R15: 00007fffc117b3a8 Allocated by task 19562: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5296 [inline] __kmalloc_noprof+0x301/0x850 mm/slub.c:5308 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] cfg80211_inform_single_bss_data+0x557/0x1de0 net/wireless/scan.c:2344 cfg80211_inform_bss_data+0x237/0x3a00 net/wireless/scan.c:3229 cfg80211_inform_bss_frame_data+0x247/0x780 net/wireless/scan.c:3320 ieee80211_bss_info_update+0x310/0xab0 net/mac80211/scan.c:230 ieee80211_rx_bss_info net/mac80211/ibss.c:1088 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1569 [inline] ieee80211_ibss_rx_queued_mgmt+0x1922/0x2f80 net/mac80211/ibss.c:1596 ieee80211_iface_process_skb net/mac80211/iface.c:1795 [inline] ieee80211_iface_work+0xbff/0x13e0 net/mac80211/iface.c:1849 cfg80211_wiphy_work+0x410/0x570 net/wireless/core.c:513 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 15: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] __rcu_free_sheaf_prepare+0x5d/0x2f0 mm/slub.c:2940 rcu_free_sheaf+0x1a/0xe0 mm/slub.c:5850 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2869 handle_softirqs+0x1ea/0xa00 kernel/softirq.c:622 run_ksoftirqd kernel/softirq.c:1076 [inline] run_ksoftirqd+0x38/0x60 kernel/softirq.c:1068 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff888026662180 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 28 bytes inside of freed 96-byte region [ffff888026662180, ffff8880266621e0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26662 flags: 0xfff00000000000(node=3D0|zone=3D1|lastcpupid=3D0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88813fe30280 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800200020 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GF= P_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2995,= tgid 2995 (kworker/u8:8), ts 29285253194, free_ts 29284937714 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1853 prep_new_page mm/page_alloc.c:1861 [inline] get_page_from_freelist+0x11a6/0x3410 mm/page_alloc.c:3941 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5221 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab mm/slub.c:3467 [inline] new_slab+0xa6/0x6c0 mm/slub.c:3525 refill_objects+0x277/0x420 mm/slub.c:7272 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x375/0x650 mm/slub.c:4652 alloc_from_pcs mm/slub.c:4750 [inline] slab_alloc_node mm/slub.c:4884 [inline] __kmalloc_cache_node_noprof+0x5a3/0x770 mm/slub.c:5428 kmalloc_node_noprof include/linux/slab.h:1077 [inline] __get_vm_area_node+0x101/0x330 mm/vmalloc.c:3215 __vmalloc_node_range_noprof+0x228/0x1630 mm/vmalloc.c:4024 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4124 alloc_thread_stack_node kernel/fork.c:357 [inline] dup_task_struct kernel/fork.c:926 [inline] copy_process+0x7fb/0x7ed0 kernel/fork.c:2090 kernel_clone+0x176/0x9e0 kernel/fork.c:2722 user_mode_thread+0xcc/0x110 kernel/fork.c:2798 call_usermodehelper_exec_work kernel/umh.c:171 [inline] call_usermodehelper_exec_work+0xcb/0x180 kernel/umh.c:157 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478 page last free pid 2995 tgid 2995 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1397 [inline] __free_frozen_pages+0x794/0x10a0 mm/page_alloc.c:2938 ___free_pages_bulk mm/kasan/shadow.c:333 [inline] __kasan_populate_vmalloc_do mm/kasan/shadow.c:385 [inline] __kasan_populate_vmalloc+0x164/0x210 mm/kasan/shadow.c:424 kasan_populate_vmalloc include/linux/kasan.h:580 [inline] alloc_vmap_area+0x95d/0x2b70 mm/vmalloc.c:2123 __get_vm_area_node+0x1ca/0x330 mm/vmalloc.c:3226 __vmalloc_node_range_noprof+0x228/0x1630 mm/vmalloc.c:4024 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4124 alloc_thread_stack_node kernel/fork.c:357 [inline] dup_task_struct kernel/fork.c:926 [inline] copy_process+0x7fb/0x7ed0 kernel/fork.c:2090 kernel_clone+0x176/0x9e0 kernel/fork.c:2722 user_mode_thread+0xcc/0x110 kernel/fork.c:2798 call_usermodehelper_exec_work kernel/umh.c:171 [inline] call_usermodehelper_exec_work+0xcb/0x180 kernel/umh.c:157 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff888026662080: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff888026662100: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc >ffff888026662180: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff888026662200: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff888026662280: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup