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AHgh+RpnRKsXQyDd1cz2E8BiUe79TzbNwViO9hes55qYm9P5Hb99VV5d12DGihmrUV4Vr9IkTDrySCmNCdL+Hw8=@vger.kernel.org X-Gm-Message-State: AFuF++l3uK1cxbdAUgvDmeThXJCl9/LkcLMxmqt5fi30tOTsNC8zr096 RSimOQwv3vX9oHo7HY4PZ6pWmh9ThJ7343AmATJQra94R2OmcL/PKTYSdDlLMBeIE3DWGyH/1k6 vRPKX0mGX0aAaLLsRBdKSAh0Bj1TkGp5uUkv2bKzNwx/pdG8g0TwPsU0fm1w= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:1307:b0:497:8f1:df07 with SMTP id 5614622812f47-4b3668217f5mr7641709b6e.7.1787752562470; Wed, 26 Aug 2026 06:56:02 -0700 (PDT) Date: Wed, 26 Aug 2026 06:56:02 -0700 In-Reply-To: X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a8ef072.1d9ded08.62e62.00b0.GAE@google.com> Subject: Re: [syzbot] [gfs2?] general protection fault in _find_first_zero_bit From: syzbot To: agruenba@redhat.com, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: general protection fault in _find_first_zero_bit Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 UID: 0 PID: 6218 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026 RIP: 0010:_find_first_zero_bit+0x29/0xb0 lib/find_bit.c:149 Code: 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 53 48 85 f6 74 46 48 89 f3 49 89 fe 49 bf 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 68 06 7b fd 49 8b 06 48 83 f8 ff RSP: 0018:ffffc90002ec76c0 EFLAGS: 00010256 RAX: 0000000000000000 RBX: 000000000000f800 RCX: 0000000000000000 RDX: ffff88802888cc40 RSI: 000000000000f800 RDI: 0000000000000000 RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff520005d8ecc R12: ffff88805dd283f0 R13: ffff88802888cc38 R14: 0000000000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125207000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000013ecc44fd000 CR3: 000000000e746000 CR4: 0000000000350ef0 Call Trace: find_first_zero_bit include/linux/find.h:391 [inline] slot_get fs/gfs2/quota.c:369 [inline] qdsb_get+0x133/0x340 fs/gfs2/quota.c:536 gfs2_quota_hold+0x191/0x5c0 fs/gfs2/quota.c:620 gfs2_dinode_dealloc+0x176/0x3f0 fs/gfs2/inode.c:529 evict_unlinked_inode fs/gfs2/super.c:1334 [inline] gfs2_evict_inode+0x11e0/0x1410 fs/gfs2/super.c:1484 evict+0x624/0xb50 fs/inode.c:822 gfs2_put_super+0x300/0x870 fs/gfs2/super.c:620 generic_shutdown_super+0x13d/0x2d0 fs/super.c:769 kill_block_super+0x44/0xa0 fs/super.c:1918 deactivate_locked_super+0xbc/0x110 fs/super.c:603 cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x73a/0x2360 kernel/exit.c:1009 do_group_exit+0x22d/0x2f0 kernel/exit.c:1152 __do_sys_exit_group kernel/exit.c:1163 [inline] __se_sys_exit_group kernel/exit.c:1161 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1161 x64_sys_call+0x2237/0x2250 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe33439ce59 Code: Unable to access opcode bytes at 0x7fe33439ce2f. RSP: 002b:00007ffe494bbc48 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fe33443233c RCX: 00007fe33439ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000016 R08: 0000000000000000 R09: 00007fe3344322ca R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe494bcf00 R13: 00007fe3344322ca R14: 000055558ebba4e8 R15: 00007ffe494c12a0 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:_find_first_zero_bit+0x29/0xb0 lib/find_bit.c:149 Code: 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 53 48 85 f6 74 46 48 89 f3 49 89 fe 49 bf 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 68 06 7b fd 49 8b 06 48 83 f8 ff RSP: 0018:ffffc90002ec76c0 EFLAGS: 00010256 RAX: 0000000000000000 RBX: 000000000000f800 RCX: 0000000000000000 RDX: ffff88802888cc40 RSI: 000000000000f800 RDI: 0000000000000000 RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff520005d8ecc R12: ffff88805dd283f0 R13: ffff88802888cc38 R14: 0000000000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125207000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000013ecc44fd000 CR3: 000000000e746000 CR4: 0000000000350ef0 ---------------- Code disassembly (best guess): 0: 90 nop 1: f3 0f 1e fa endbr64 5: 41 57 push %r15 7: 41 56 push %r14 9: 41 55 push %r13 b: 41 54 push %r12 d: 53 push %rbx e: 48 85 f6 test %rsi,%rsi 11: 74 46 je 0x59 13: 48 89 f3 mov %rsi,%rbx 16: 49 89 fe mov %rdi,%r14 19: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15 20: fc ff df 23: 48 89 f8 mov %rdi,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) <-- trapping instruction 2f: 74 08 je 0x39 31: 4c 89 f7 mov %r14,%rdi 34: e8 68 06 7b fd call 0xfd7b06a1 39: 49 8b 06 mov (%r14),%rax 3c: 48 83 f8 ff cmp $0xffffffffffffffff,%rax Tested on: commit: 8ea0df12 gfs2: Add meta inode validation to prevent co.. git tree: git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2.git console output: https://syzkaller.appspot.com/x/log.txt?x=15ca0579580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f8dd02b32fb43dc7 dashboard link: https://syzkaller.appspot.com/bug?extid=cb79de2cc8b76fbf474f compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Note: no patches were applied.