From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f71.google.com (mail-oo1-f71.google.com [209.85.161.71]) (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 4B1BE325488 for ; Wed, 18 Feb 2026 08:47:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771404428; cv=none; b=Ai1GZwEA8pshlqumHkY/AqDZVCysVrHlILtnQmLl2MOZ5BAh/UYgVckTDsg6PNGMRXCKf7zaFNdaBxujFmPoKH41aNaw3FBvS8p7mFCCNEb5eQey1bs/mU/wXqq3uMVayd12ab4KeFcBhCrQU9RQ9VljMjUOzxSr1kGGoPmkpTY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771404428; c=relaxed/simple; bh=Esdzk9VSfB+lTanDTVJE2rQhGfxzfyI1dUMsdig+Em8=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To:Cc: Content-Type; 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006d021491bc7-679a650d096mr1037503eaf.80.1771404426124; Wed, 18 Feb 2026 00:47:06 -0800 (PST) Date: Wed, 18 Feb 2026 00:47:06 -0800 In-Reply-To: <20260218025207.1425553-1-joannelkoong@gmail.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69957c8a.a70a0220.2c38d7.011b.GAE@google.com> Subject: [syzbot ci] Re: io_uring: add kernel-managed buffer rings From: syzbot ci To: asml.silence@gmail.com, axboe@kernel.dk, bernd@bsbernd.com, csander@purestorage.com, hch@infradead.org, io-uring@vger.kernel.org, joannelkoong@gmail.com Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot ci has tested the following series [v2] io_uring: add kernel-managed buffer rings https://lore.kernel.org/all/20260218025207.1425553-1-joannelkoong@gmail.com * [PATCH v2 1/9] io_uring/memmap: chunk allocations in io_region_allocate_pages() * [PATCH v2 2/9] io_uring/kbuf: add support for kernel-managed buffer rings * [PATCH v2 3/9] io_uring/kbuf: support kernel-managed buffer rings in buffer selection * [PATCH v2 4/9] io_uring/kbuf: add buffer ring pinning/unpinning * [PATCH v2 5/9] io_uring/kbuf: return buffer id in buffer selection * [PATCH v2 6/9] io_uring/kbuf: add recycling for kernel managed buffer rings * [PATCH v2 7/9] io_uring/kbuf: add io_uring_is_kmbuf_ring() * [PATCH v2 8/9] io_uring/kbuf: export io_ring_buffer_select() * [PATCH v2 9/9] io_uring/cmd: set selected buffer index in __io_uring_cmd_done() and found the following issue: general protection fault in io_remove_buffers_legacy Full report is available here: https://ci.syzbot.org/series/ddeaf464-c69b-4166-b0cf-53c9d51e4820 *** general protection fault in io_remove_buffers_legacy tree: torvalds URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux base: 2961f841b025fb234860bac26dfb7fa7cb0fb122 arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/ab5ad5aa-2757-4d66-a2c5-391a8417535d/config C repro: https://ci.syzbot.org/findings/061747e2-36f1-499b-ac34-38cefffbce63/c_repro syz repro: https://ci.syzbot.org/findings/061747e2-36f1-499b-ac34-38cefffbce63/syz_repro Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 1 UID: 0 PID: 5967 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:__list_del_entry_valid_or_report+0x25/0x190 lib/list_debug.c:49 Code: 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 53 48 89 fb 49 bd 00 00 00 00 00 fc ff df 48 83 c7 08 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 05 e8 df 8c 77 fd 4c 8b 7b 08 48 89 d8 48 c1 e8 RSP: 0018:ffffc900040a7b68 EFLAGS: 00010202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 1ffff11035ee2732 RDX: 1ffff11035ee2730 RSI: 00000000ffffffff RDI: 0000000000000008 RBP: dffffc0000000000 R08: ffff8881af7139b7 R09: 0000000000000000 R10: ffff8881af7139a0 R11: ffffed1035ee2737 R12: ffff8881af713980 R13: dffffc0000000000 R14: 00000000ffffffff R15: 0000000000000000 FS: 0000555560587500(0000) GS:ffff8882a9466000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001000 CR3: 0000000175cd2000 CR4: 00000000000006f0 Call Trace: __list_del_entry_valid include/linux/list.h:132 [inline] __list_del_entry include/linux/list.h:223 [inline] list_del include/linux/list.h:237 [inline] io_remove_buffers_legacy+0x139/0x310 io_uring/kbuf.c:533 io_put_bl+0x62/0x120 io_uring/kbuf.c:548 io_register_pbuf_ring+0x6c0/0x7d0 io_uring/kbuf.c:855 __io_uring_register io_uring/register.c:838 [inline] __do_sys_io_uring_register io_uring/register.c:1024 [inline] __se_sys_io_uring_register+0xc3e/0x19a0 io_uring/register.c:1001 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f056859bf79 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 ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fffd8dcfaf8 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab RAX: ffffffffffffffda RBX: 00007f0568815fa0 RCX: 00007f056859bf79 RDX: 0000200000000040 RSI: 0000000000000016 RDI: 0000000000000004 RBP: 00007f05686327e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0568815fac R14: 00007f0568815fa0 R15: 00007f0568815fa0 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:__list_del_entry_valid_or_report+0x25/0x190 lib/list_debug.c:49 Code: 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 53 48 89 fb 49 bd 00 00 00 00 00 fc ff df 48 83 c7 08 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 05 e8 df 8c 77 fd 4c 8b 7b 08 48 89 d8 48 c1 e8 RSP: 0018:ffffc900040a7b68 EFLAGS: 00010202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 1ffff11035ee2732 RDX: 1ffff11035ee2730 RSI: 00000000ffffffff RDI: 0000000000000008 RBP: dffffc0000000000 R08: ffff8881af7139b7 R09: 0000000000000000 R10: ffff8881af7139a0 R11: ffffed1035ee2737 R12: ffff8881af713980 R13: dffffc0000000000 R14: 00000000ffffffff R15: 0000000000000000 FS: 0000555560587500(0000) GS:ffff8882a9466000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f25f1e17095 CR3: 0000000175cd2000 CR4: 00000000000006f0 ---------------- Code disassembly (best guess): 0: 90 nop 1: 90 nop 2: 90 nop 3: 90 nop 4: 90 nop 5: f3 0f 1e fa endbr64 9: 41 57 push %r15 b: 41 56 push %r14 d: 41 55 push %r13 f: 41 54 push %r12 11: 53 push %rbx 12: 48 89 fb mov %rdi,%rbx 15: 49 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%r13 1c: fc ff df 1f: 48 83 c7 08 add $0x8,%rdi 23: 48 89 f8 mov %rdi,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction 2f: 74 05 je 0x36 31: e8 df 8c 77 fd call 0xfd778d15 36: 4c 8b 7b 08 mov 0x8(%rbx),%r15 3a: 48 89 d8 mov %rbx,%rax 3d: 48 rex.W 3e: c1 .byte 0xc1 3f: e8 .byte 0xe8 *** If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com --- This report is generated by a bot. It may contain errors. syzbot ci engineers can be reached at syzkaller@googlegroups.com.