From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f71.google.com (mail-oa1-f71.google.com [209.85.160.71]) (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 0D1A6306754 for ; Sun, 11 Oct 2026 06:54:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791701666; cv=none; b=Ef3ymlk9E4dDeZTlMQZMEgFscHi89B+O1NMElcGbRfH279EF0tx99YysXhv33Mch7NAiezif3QH5GkpTMChGBcnBgKGtC3z+r3mzMeuuwzFaWUUtu8//8h7pH1oDphMJiE1F/QdxxxTCuTqrf33XB2NJGmj1REHXj65nVJ0/dLs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791701666; c=relaxed/simple; bh=1zHjCZpEBXLAHFckqN0jJnIxtZ8o8D51gPCiLGzfbEQ=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=hLdWcOZnL9EscGWyt93P03Ps95Wc1aXUuRxRXRTx6DXGfaJYLHU/D8yo1RU1lupCTkKdkHJUFx8gagcZ+EGkymUfv/QPdd/e8y+ITAPvOjz8FsmvtVZpF2IoeFJ5sIgeBfz7Ta/Ob+ai4YVX4WwEH40GO5Rm6PnRms6mXZSOvdI= 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=209.85.160.71 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-oa1-f71.google.com with SMTP id 586e51a60fabf-4a68926c8c4so277762fac.0 for ; Sat, 10 Oct 2026 23:54:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791701664; x=1792306464; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=MH8PLyqXhed2HbAQNHa2OspLGGBPys6BRDYg9XGjK+c=; b=jzxaAm6SE19EmsjgtgtCh+2nmgp5a3PcgFINYyq/+m4Rb/Oq56OO6VjOUpcTz/8IR1 RxqVoZwZq5l+TYO7W/QmksB5fkssRm2Vfv2ZBQDJrrsm7qOyi+gn6YjbVyhu7bSOVsZ5 NElekou/2tFpLKFinkOv41meTUN00vMiWBX5m5xIcDRlrLTK/Z9q9QQ8bOQcHHbwujvU 1Ih99X/WHwYQPBupcsczMkFf1ImiuSHTvZxZTk9MJtCqK9wqZhXEgJT8U9SPpUKpbFU1 0RtCNFqSqXGQIVlL094AovCHzuvhZvA7YMw0CdMMPUYTk9Uu22EMAWM3wCswXO4aNBDb 9IXg== X-Forwarded-Encrypted: i=1; AKwUvBxfIUE0qyQ7t2UcGzBFGthm0nIDBEx8rJd1K5KaJ3e7vb5Bsgu0UiPdhlfOGFcGYAe3JVLd4vg=@vger.kernel.org X-Gm-Message-State: AFq9FYIMd/AOLCwa6R1s8pZpQWSMAdXTXVNTC/DYkR2yp1hReS8slDpE kg/TQ1kO0Vlxkg7/8v/Q+zsSqzpF8FV/kUrlr4oDkecLRr/DGjGij9pxXcILqDuZsc3iEWIghsN oTdGXDuLFxLlW1PWubtsp1D5rUhHel0DnIoBNUSnuA+M0vePdzFumHA/csls= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:4fce:b0:4e5:c2b4:33a9 with SMTP id 5614622812f47-50c53ca2ae1mr6028911b6e.46.1791701664034; Sat, 10 Oct 2026 23:54:24 -0700 (PDT) Date: Sat, 10 Oct 2026 23:54:24 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6acb32a0.bbc4c7f9.15faa7.007c.GAE@google.com> Subject: [syzbot] [net?] [nfs?] KASAN: null-ptr-deref Read in xprt_reserve From: syzbot To: Dai.Ngo@oracle.com, anna@kernel.org, cel@kernel.org, davem@davemloft.net, edumazet@kernel.org, horms@kernel.org, jlayton@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, neil@brown.name, netdev@vger.kernel.org, okorniev@redhat.com, pabeni@redhat.com, syzkaller-bugs@googlegroups.com, tom@talpey.com, trondmy@kernel.org Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 6c377d19d4a5 Merge tag 'ext4_for_linus-7.3-rc7' of git://g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1223300d580000 kernel config: https://syzkaller.appspot.com/x/.config?x=4118aaa2d227be26 dashboard link: https://syzkaller.appspot.com/bug?extid=ae55a0fac80c73c938ac compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/c5f7458da164/disk-6c377d19.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/8ae69062b78e/vmlinux-6c377d19.xz kernel image: https://storage.googleapis.com/syzbot-assets/602017f8f9bb/bzImage-6c377d19.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ae55a0fac80c73c938ac@syzkaller.appspotmail.com ================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:82 [inline] BUG: KASAN: null-ptr-deref in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] BUG: KASAN: null-ptr-deref in xprt_throttle_congested net/sunrpc/xprt.c:1708 [inline] BUG: KASAN: null-ptr-deref in xprt_reserve+0xe2/0x2c0 net/sunrpc/xprt.c:1948 Read of size 8 at addr 0000000000000628 by task syz.8.3118/20390 CPU: 1 UID: 0 PID: 20390 Comm: syz.8.3118 Tainted: G S L syzkaller #0 PREEMPT(full) Tainted: [S]=CPU_OUT_OF_SPEC, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 kasan_report+0x117/0x150 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200 instrument_atomic_read include/linux/instrumented.h:82 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] xprt_throttle_congested net/sunrpc/xprt.c:1708 [inline] xprt_reserve+0xe2/0x2c0 net/sunrpc/xprt.c:1948 __rpc_execute+0x526/0x1280 net/sunrpc/sched.c:947 rpc_execute+0x1c1/0x390 net/sunrpc/sched.c:1023 rpc_run_task+0x4a6/0x660 net/sunrpc/clnt.c:1269 rpc_ping_noreply net/sunrpc/clnt.c:2944 [inline] rpc_create_xprt+0x452/0xa90 net/sunrpc/clnt.c:494 rpc_create+0x649/0x900 net/sunrpc/clnt.c:619 gssp_rpc_create net/sunrpc/auth_gss/gss_rpc_upcall.c:107 [inline] set_gssp_clnt+0x188/0x2d0 net/sunrpc/auth_gss/gss_rpc_upcall.c:131 write_gssp+0x21e/0x310 net/sunrpc/auth_gss/svcauth_gss.c:1423 pde_write fs/proc/inode.c:330 [inline] proc_reg_write+0x1e9/0x2e0 fs/proc/inode.c:342 vfs_write+0x296/0xba0 fs/read_write.c:685 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f44e699e1d9 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:00007f44e78be028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f44e6c25fa0 RCX: 00007f44e699e1d9 RDX: 0000000000000001 RSI: 0000200000000300 RDI: 0000000000000005 RBP: 00007f44e6a35888 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f44e6c26038 R14: 00007f44e6c25fa0 R15: 00007ffdb88808e8 ================================================================== --- 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