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AHgh+RqBOaxLzyDxU+m6u6M5Vr6qJROM6of/sHP4JtPVRXpGNNIu1Do7HihoAORHgOgn3vy/+MVQudCRpL1J0M4=@vger.kernel.org X-Gm-Message-State: AFuF++n77ujPHRldMtdvZkPwDe4zxV7fQ4QDjJqzHxnTzmr0msSi7gcf G/yclR7oTZJk8ujcFIodQK/EJvIHgNdzzUHbK+dV+kIg/JOAYWNJYF3CTHGm26Cx0eBusJ28K// xHBsuUawvD/U1PQ/hKQhGV1wo3M0fvNisE52M6CZ8NZ6ZAwpxabjnAzH6nfw= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:17a4:b0:4b2:8dbe:b596 with SMTP id 5614622812f47-4b3668b9b23mr13234696b6e.2.1787824896768; Thu, 27 Aug 2026 03:01:36 -0700 (PDT) Date: Thu, 27 Aug 2026 03:01:36 -0700 In-Reply-To: <6a8faf18.4d659fcc.734b4.0009.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a900b00.1d9ded08.62e62.00cf.GAE@google.com> Subject: Re: [syzbot] [nvme?] KASAN: slab-use-after-free Read in nvmet_port_subsys_allow_link From: syzbot To: hch@lst.de, kch@nvidia.com, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, sagi@grimberg.me, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 818bebeb63dd drm/xe: Don't hand out the flat CCS storage a.. git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git console output: https://syzkaller.appspot.com/x/log.txt?x=1458e579580000 kernel config: https://syzkaller.appspot.com/x/.config?x=ccca94d2c01b9e78 dashboard link: https://syzkaller.appspot.com/bug?extid=b0996ac2197dd7420c3e compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11ab6d49580000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+b0996ac2197dd7420c3e@syzkaller.appspotmail.com Oops: general protection fault, probably for non-canonical address 0xdffffc0000000022: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000110-0x0000000000000117] CPU: 2 UID: 0 PID: 6022 Comm: syz-executor823 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:nvmet_port_subsys_allow_link+0x108/0x390 drivers/nvme/target/configfs.c:1076 Code: 00 00 4d 89 66 10 48 c7 c7 e0 d9 f3 8f 4d 8d af 10 01 00 00 e8 29 aa 1f 05 4c 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 f0 01 00 00 49 8b 9f 10 01 00 00 4c 39 eb 0f 84 RSP: 0018:ffffc9000283fc88 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: ffff8880271f8498 RCX: 0000000000000000 RDX: 0000000000000022 RSI: 0000000000000008 RDI: 0000000000000001 RBP: ffffffff8ff44260 R08: 0000000000000001 R09: fffffbfff1fe7b3d R10: ffffffff8ff3d9ef R11: 0000000000000000 R12: ffff88802c543000 R13: 0000000000000110 R14: ffff88803dc39b80 R15: 0000000000000000 FS: 00007f53b85796c0(0000) GS:ffff8880d5da2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f53b5572ff8 CR3: 0000000055990000 CR4: 0000000000352ef0 Call Trace: configfs_symlink+0x540/0x11f0 fs/configfs/symlink.c:196 vfs_symlink fs/namei.c:5794 [inline] vfs_symlink+0x178/0x4d0 fs/namei.c:5773 filename_symlinkat+0x2a6/0x560 fs/namei.c:5819 __do_sys_symlinkat fs/namei.c:5839 [inline] __se_sys_symlinkat fs/namei.c:5834 [inline] __x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5834 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f53b85ae459 Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f53b85791f8 EFLAGS: 00000246 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 00007f53b861b028 RCX: 00007f53b85ae459 RDX: 00007f53b861b028 RSI: 00000000ffffff9c RDI: 00007f53b861b060 RBP: 00007f53b861b060 R08: 00007f53b85796c0 R09: 00007f53b85796c0 R10: 00007f53b85796c0 R11: 0000000000000246 R12: ffffffffffffffd0 R13: 0000000000000010 R14: 00007ffff5cb1e50 R15: 00007ffff5cb1f38 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:nvmet_port_subsys_allow_link+0x108/0x390 drivers/nvme/target/configfs.c:1076 Code: 00 00 4d 89 66 10 48 c7 c7 e0 d9 f3 8f 4d 8d af 10 01 00 00 e8 29 aa 1f 05 4c 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 f0 01 00 00 49 8b 9f 10 01 00 00 4c 39 eb 0f 84 RSP: 0018:ffffc9000283fc88 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: ffff8880271f8498 RCX: 0000000000000000 RDX: 0000000000000022 RSI: 0000000000000008 RDI: 0000000000000001 RBP: ffffffff8ff44260 R08: 0000000000000001 R09: fffffbfff1fe7b3d R10: ffffffff8ff3d9ef R11: 0000000000000000 R12: ffff88802c543000 R13: 0000000000000110 R14: ffff88803dc39b80 R15: 0000000000000000 FS: 00007f53b85796c0(0000) GS:ffff8880d5da2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f53b5572ff8 CR3: 0000000055990000 CR4: 0000000000352ef0 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 4d 89 66 10 mov %r12,0x10(%r14) 6: 48 c7 c7 e0 d9 f3 8f mov $0xffffffff8ff3d9e0,%rdi d: 4d 8d af 10 01 00 00 lea 0x110(%r15),%r13 14: e8 29 aa 1f 05 call 0x51faa42 19: 4c 89 ea mov %r13,%rdx 1c: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 23: fc ff df 26: 48 c1 ea 03 shr $0x3,%rdx * 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction 2e: 0f 85 f0 01 00 00 jne 0x224 34: 49 8b 9f 10 01 00 00 mov 0x110(%r15),%rbx 3b: 4c 39 eb cmp %r13,%rbx 3e: 0f .byte 0xf 3f: 84 .byte 0x84 --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.