From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f77.google.com (mail-oo1-f77.google.com [209.85.161.77]) (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 13C79345740 for ; Fri, 6 Feb 2026 09:24:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770369875; cv=none; b=g90fykL8MK9rE4YsFW/s+P0XmXym2K2vr995wldatJujLEi0fywAAHQXa2qf9BKwgqPA30e5eUHCv7RlREPdlEAlVcMdVgN6Yzgr0mPTwcRjo5/kT7TC2pUDcbxNB5FzxwykFFEmnurjlU21vx18kEJ2etavigQ10VmApW8SbRc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770369875; c=relaxed/simple; bh=DG9WaadmWeoGNg96d/ePOxs9xvJYENGMzVHTAiKQMFU=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=OkEPOW2Bmr99om//3x1B7xw3jyzcoHcONT6IJANRuDkLpJ7FO65Itx2v8qllVezIrM/JcHoRHw4Ax3+Wsf8evzdpMpyQDaJCKSFl73YzL/UGZz44y4zf0OWgwmTRrg+9sbapFq6Q33BZT4HCVgs0ELIpqKfN1A4iBdf2uEWULVQ= 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=209.85.161.77 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-f77.google.com with SMTP id 006d021491bc7-66b70fffe1dso7535161eaf.2 for ; Fri, 06 Feb 2026 01:24:34 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770369874; x=1770974674; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=pCV5U+fp1hQb/l/EWlCtDcH41LkYbYc4PVdD616mZHw=; b=JhLDvni2+kGYI35DMwDNjqNDUa2zadXqVlUWTx7BuwQJrq4EANTafLUKzAoGtgW86J 8EdA4Lt3wXQKlFekcPSXp+gxePaXj/mA9kuKguXRy7g8GT3DCR3whCgfYqCTOXGIL0uo KhzF5KpizJB+F+AQaom2AEAVpY8dqGPtBZ4aZ9yb/HBGit9BUenu3hoIcCNK1krgAsNu qu/2MDI9z7uD5cyjZCx+RdbXDbny4adgXn1SlokqYED/PHP0X2xZ0qd2gQuPFkoYT+PB ABIzr/pvEmx+O+FecLUtOyMUaU2WwFS8odase19o96J4+eP439xj41YHTZj7FDtpe0kW dFgg== X-Forwarded-Encrypted: i=1; AJvYcCUKsV2RVaQEyIopFjkdxikuoLCABaJ0kZUzQ4+2Z+yQdXgomyTQdwoG9Vw4fOX6ym7l1R1Dv0TMuVZet/E=@vger.kernel.org X-Gm-Message-State: AOJu0YzE2tUcl+buQ02eyEnWY6jlKrupGpE4Ef5Y6PB35nF3KGC5LLco 1OtLKebuSQ6SwVST9z4AVFGKNpTmd8uvqMKBXmfBgVSJL9kBxQFlWtcTUdQCuOjdptKvNxV5YTr alqiRmWC/otxQv7cdEp5tp+3Su7UMqW/PYyDmtiYJnaMRPJxPPAPbCNyfRhs= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4b8c:b0:65f:6053:756d with SMTP id 006d021491bc7-66d0a56ec68mr1050901eaf.28.1770369874006; Fri, 06 Feb 2026 01:24:34 -0800 (PST) Date: Fri, 06 Feb 2026 01:24:33 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6985b351.a00a0220.37c87e.0034.GAE@google.com> Subject: [syzbot] [afs?] KASAN: slab-use-after-free Read in __radix_tree_replace From: syzbot To: dhowells@redhat.com, linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org, marc.dionne@auristor.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: d358e5254674 Merge tag 'for-6.19/dm-changes' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=10650592580000 kernel config: https://syzkaller.appspot.com/x/.config?x=37bf6cac94c6b2f8 dashboard link: https://syzkaller.appspot.com/bug?extid=8d4b939fcb6c6acbfe97 compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-d358e525.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/74b71d0845ac/vmlinux-d358e525.xz kernel image: https://storage.googleapis.com/syzbot-assets/7b362bbbe01b/bzImage-d358e525.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+8d4b939fcb6c6acbfe97@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in replace_slot lib/radix-tree.c:827 [inline] BUG: KASAN: slab-use-after-free in __radix_tree_replace+0x317/0x360 lib/radix-tree.c:890 Read of size 1 at addr ffff88804f6939c2 by task syz.0.1096/11903 CPU: 2 UID: 0 PID: 11903 Comm: syz.0.1096 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~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 replace_slot lib/radix-tree.c:827 [inline] __radix_tree_replace+0x317/0x360 lib/radix-tree.c:890 idr_alloc_u32+0x1fd/0x2f0 lib/idr.c:52 idr_alloc_cyclic+0x10b/0x230 lib/idr.c:125 afs_alloc_cell fs/afs/cell.c:209 [inline] afs_lookup_cell+0x11d1/0x1900 fs/afs/cell.c:278 afs_parse_source fs/afs/super.c:292 [inline] afs_parse_param+0x5c4/0x970 fs/afs/super.c:330 vfs_parse_fs_param+0x20b/0x3c0 fs/fs_context.c:146 vfs_fsconfig_locked fs/fsopen.c:303 [inline] __do_sys_fsconfig+0x930/0xbe0 fs/fsopen.c:473 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe8/0x680 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f84579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f4bd555c EFLAGS: 00000296 ORIG_RAX: 00000000000001af RAX: ffffffffffffffda RBX: 000000000000000d RCX: 0000000000000001 RDX: 0000000080000000 RSI: 0000000080000180 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 11898: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:339 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:365 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270 radix_tree_node_alloc.constprop.0+0x7c/0x350 lib/radix-tree.c:276 idr_get_free+0x528/0xa30 lib/radix-tree.c:1506 idr_alloc_u32+0x190/0x2f0 lib/idr.c:46 idr_alloc_cyclic+0x10b/0x230 lib/idr.c:125 afs_alloc_cell fs/afs/cell.c:209 [inline] afs_lookup_cell+0x11d1/0x1900 fs/afs/cell.c:278 afs_parse_source fs/afs/super.c:292 [inline] afs_parse_param+0x5c4/0x970 fs/afs/super.c:330 vfs_parse_fs_param+0x20b/0x3c0 fs/fs_context.c:146 vfs_fsconfig_locked fs/fsopen.c:303 [inline] __do_sys_fsconfig+0x930/0xbe0 fs/fsopen.c:473 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe8/0x680 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Freed by task 0: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6668 [inline] kmem_cache_free+0x2d8/0x770 mm/slub.c:6779 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0x79c/0x15f0 kernel/rcu/tree.c:2857 handle_softirqs+0x219/0x950 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 Last potentially related work creation: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556 __call_rcu_common.constprop.0+0xa5/0xa10 kernel/rcu/tree.c:3119 radix_tree_node_free lib/radix-tree.c:310 [inline] delete_node+0x1fc/0x8d0 lib/radix-tree.c:573 __radix_tree_delete+0x193/0x3d0 lib/radix-tree.c:1379 radix_tree_delete_item+0xea/0x230 lib/radix-tree.c:1430 afs_cell_destroy+0x1db/0x310 fs/afs/cell.c:580 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0x79c/0x15f0 kernel/rcu/tree.c:2857 handle_softirqs+0x219/0x950 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 The buggy address belongs to the object at ffff88804f6939c0 which belongs to the cache radix_tree_node of size 576 The buggy address is located 2 bytes inside of freed 576-byte region [ffff88804f6939c0, ffff88804f693c00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4f690 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff88804d3b9e01 flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 04fff00000000040 ffff88801b44cc80 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080170017 00000000f5000000 ffff88804d3b9e01 head: 04fff00000000040 ffff88801b44cc80 dead000000000122 0000000000000000 head: 0000000000000000 0000000080170017 00000000f5000000 ffff88804d3b9e01 head: 04fff00000000002 ffffea00013da401 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Reclaimable, gfp_mask 0x152810(GFP_NOWAIT|__GFP_RECLAIMABLE|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 11848, tgid 11847 (syz.2.1089), ts 643758920019, free_ts 199291394557 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1846 prep_new_page mm/page_alloc.c:1854 [inline] get_page_from_freelist+0xd0b/0x31a0 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x25f/0x2430 mm/page_alloc.c:5210 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab mm/slub.c:3248 [inline] new_slab+0x2c3/0x430 mm/slub.c:3302 ___slab_alloc+0xe18/0x1c90 mm/slub.c:4656 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] kmem_cache_alloc_lru_noprof+0x451/0x770 mm/slub.c:5282 xas_alloc+0x34f/0x460 lib/xarray.c:378 xas_create+0x72b/0x1460 lib/xarray.c:685 xas_store+0x90/0x1910 lib/xarray.c:795 shmem_add_to_page_cache+0x7b7/0xa70 mm/shmem.c:922 shmem_alloc_and_add_folio+0x662/0xc20 mm/shmem.c:1958 shmem_get_folio_gfp+0x67f/0x1610 mm/shmem.c:2556 shmem_fault+0x1fe/0xa00 mm/shmem.c:2757 __do_fault+0x10d/0x490 mm/memory.c:5320 page last free pid 7671 tgid 7671 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x7df/0x1170 mm/page_alloc.c:2943 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4c/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:349 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270 getname_flags.part.0+0x4c/0x550 fs/namei.c:146 getname_flags+0x93/0xf0 include/linux/audit.h:345 getname include/linux/fs.h:2498 [inline] getname_maybe_null include/linux/fs.h:2505 [inline] getname_maybe_null include/linux/fs.h:2502 [inline] vfs_fstatat+0xe1/0xf0 fs/stat.c:370 __do_sys_newfstatat+0x97/0x120 fs/stat.c:542 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88804f693880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88804f693900: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc >ffff88804f693980: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ^ ffff88804f693a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804f693a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi --- 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