From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f182.google.com (mail-qk1-f182.google.com [209.85.222.182]) (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 AE0618003D for ; Sun, 7 Jun 2026 02:17:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780798633; cv=none; b=svdTHU+l4VrGAO/XlBeGtOaLZeCdH+6TixZII+IbruquqIwVWPdcvgbCZuWshIq9yw6VDnV1Ul377bhUf+w67W46dwwxM2eAlZ8URK0zns630btH1DLFDblRIIVsx1I/tkPpPEotO/txsptRYAFgE+aCQ0U81im8K+7DW21CePE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780798633; c=relaxed/simple; bh=QmQj8pn1BszsydvtP6xCa24DN4fl+NL/AwBtOqHlzzQ=; h=From:Content-Type:Mime-Version:Subject:Message-Id:Date:Cc:To; b=oFzZovQlADApptaSSuFqt2jdXZ5+jqOPTmGORmTfVT4Ine2LDLXtPuBIE97PQgyd1arlsggEGTNZQ8YYSc7ELrQgj16vJC0btqo++6kjcDUZynRRn9iohyJGWOcV4uF+cG7NKN+ywVKic/+7v7wwSyyiiPrecE0eQCOwjRIf+Q0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=fUfgKYTc; arc=none smtp.client-ip=209.85.222.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="fUfgKYTc" Received: by mail-qk1-f182.google.com with SMTP id af79cd13be357-915b5ce94c7so157823885a.2 for ; Sat, 06 Jun 2026 19:17:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1780798630; x=1781403430; darn=vger.kernel.org; h=to:cc:date:message-id:subject:mime-version :content-transfer-encoding:from:from:to:cc:subject:date:message-id :reply-to; bh=HyzTkYCGGMBYiZr90+zq7gb1XnJwNW0EoAweHvtNSjY=; b=fUfgKYTcvZmSDcKPfcg+bGzBr7h9j6wwh4JqSjHdHCwnjAjLegZ3dZIRiiut0fXIHg 0Cr7jc/FTiFY3hdJx5nW0I3WIMX5LOvZj8hLx2vzGU6vgXwY7qUaqzxSKT6GH2qbfpq7 o9WHGAb3DZZURTCOhk7FRmEOZ9cDjoj2tHSMFxAY90yauCkqqgrHbP5YdlaAuuvOSCxa V96LOGJ1PlGybEnpQo16oCUSs8M2TMDsIgniUbjLogEnbl5V5SccgAnSDA7EPyO5Z4OR qnAnBg5UFQASsb2+QqMU5Q7qB0leImXn9dMJcHBRkt6lqEStoJYX96WZbi3vZvK2NkWZ oahg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780798630; x=1781403430; h=to:cc:date:message-id:subject:mime-version :content-transfer-encoding:from:x-gm-gg:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=HyzTkYCGGMBYiZr90+zq7gb1XnJwNW0EoAweHvtNSjY=; b=qfWDbcfk8+q2C87aiIHvNRQny9EJ97Zqp8cMqlsbsVvcdJ3XphGY9ZZrRcELF0rMJ9 eagNoTXPkL0K486U8IT8wW+xdYIDglJ0FTadmi1OemNSQwOi/xsbbxV+i0MOP7BNKDAE 47z68T6Vjuchx3El/a2MKi4vY9tfoY0CARP2E2vEVqNAi/Gz2l8ehavgsQ6J86ZZuoV0 7jscyiYXZr1fEvqUg0of0kbHqcnO488ycqTTUYz3vSYxiRbjIPH470s5NbmWDY/YGsuP PovCMJDk0sb7r21T4bODYgObGFrxtWiC+SWY8w47FkvR46ve0KUXWNJMfxicXFmnpnzQ tmzg== X-Forwarded-Encrypted: i=1; AFNElJ80rUFtBilNe1rii5NNsJsaUiPjMAg7hqWRiuiu11iGiWxp+4uNIUI5GsujkPcPdiuj7GdJy1XUu+v5EGs=@vger.kernel.org X-Gm-Message-State: AOJu0YyojH80Xge7Dy4w1UrrHlyJqibveMOFXaq9VqkclLB9B/2mzL2u D3tWQE3LW+vkYgLr4IzqEt4pejWuh/+A75xnNhFxLHrNyQM/kfW2jw/W X-Gm-Gg: Acq92OGvyCObpFdjpcgUj9FdPcmfk0P1RTQQKPZj3IFoxdVYrVhVnk7D8JA9RK92lgK 2mvz/5wmlcn63JtCrwxF+bc/i1Ju8QbccKlbwnbG0GTMxWJajdDhH4XtijyHe6tWvyED0a4Novc vordZ6uaB26YxLmKBSfBK90CNvuWVQXlSEkCdJePaMKg399UJcqFHENM6pZjVadHZI4qBSCSW3V Bn7Qoj/EoxMaWt2+VAEeouKlYhksR/UxUuEgbN5ExYcEvhVvscE3KrkMhGSqLDuD2AuhqEI/jHE cmQxKUj/AnHidYiKSKMzMPgUpb2lRrhQtD6Wl3GUGhe50HXSF5zR3mRrCLAh/bd4mpvAUBLpaLB 49AlOjBXh5RV6ai6b4TLfJr2Pk2eVoyG8uR7FN9nKTyQ3PDMRepCxBAnVneqhqZ8a1BbloQ6XP7 B3arvjzj1uidifbB34hupPeufkySvsemkQJmfsz81LHFv3bFTM2A+GbxH0Z1uOGF2r6O0EVo9ZL 4A= X-Received: by 2002:a05:620a:448d:b0:915:351b:3ae5 with SMTP id af79cd13be357-915a9daec07mr1693851685a.41.1780798630474; Sat, 06 Jun 2026 19:17:10 -0700 (PDT) Received: from smtpclient.apple ([2601:985:4601:5df0:fceb:48b4:c445:f78d]) by smtp.gmail.com with ESMTPSA id af79cd13be357-9158a37bae6sm1320986085a.31.2026.06.06.19.17.09 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 06 Jun 2026 19:17:09 -0700 (PDT) From: Shuangpeng Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3864.600.51.1.1\)) Subject: [BUG] KASAN: slab-use-after-free in xprt_put Message-Id: <4EB31731-B511-44E6-9019-760EED0A2BD1@gmail.com> Date: Sat, 6 Jun 2026 22:16:38 -0400 Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org To: trondmy@kernel.org, anna@kernel.org X-Mailer: Apple Mail (2.3864.600.51.1.1) Hi Kernel Maintainers, I hit the following KASAN report while testing current upstream kernel: KASAN: slab-use-after-free in xprt_put on commit: e8c2f9fdadee7cbc75134dc463c1e0d856d6e5c7 (May 25 2026) To help trigger the bug more reliably, we applied a minimal diagnostic = patch that only adds delays and print statements. The reproducer and .config files are here. https://gist.github.com/shuangpengbai/98a27c1e3c0dc5489f117efa7c254593 I=E2=80=99m happy to test debug patches or provide additional = information. Reported-by: Shuangpeng Bai [ 170.638952][ T24] = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D [ 170.641053][ T24] BUG: KASAN: slab-use-after-free in xprt_put = (./include/linux/instrumented.h:112 = ./include/linux/atomic/atomic-instrumented.h:400 = ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 = ./include/linux/refcount.h:450 ./include/linux/kref.h:64 = net/sunrpc/xprt.c:2195) [ 170.643027][ T24] Write of size 4 at addr ffff8881092e1000 by task = kworker/1:0/24 [ 170.645020][ T24] [ 170.645344][ T24] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + = PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 170.645349][ T24] Workqueue: events rpc_free_client_work [ 170.645375][ T24] Call Trace: [ 170.645390][ T24] [ 170.645394][ T24] dump_stack_lvl (lib/dump_stack.c:94 = lib/dump_stack.c:120) [ 170.645451][ T24] print_report (mm/kasan/report.c:378 = mm/kasan/report.c:482) [ 170.645514][ T24] kasan_report (mm/kasan/report.c:595) [ 170.645525][ T24] kasan_check_range (mm/kasan/generic.c:? = mm/kasan/generic.c:200) [ 170.645530][ T24] xprt_put (./include/linux/instrumented.h:112 = ./include/linux/atomic/atomic-instrumented.h:400 = ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 = ./include/linux/refcount.h:450 ./include/linux/kref.h:64 = net/sunrpc/xprt.c:2195) [ 170.645535][ T24] rpc_free_client_work (net/sunrpc/clnt.c:991) [ 170.645541][ T24] process_scheduled_works (kernel/workqueue.c:3314 = kernel/workqueue.c:3397) [ 170.645557][ T24] worker_thread (kernel/workqueue.c:3478) [ 170.645577][ T24] kthread (kernel/kthread.c:436) [ 170.645590][ T24] ret_from_fork (arch/x86/kernel/process.c:158) [ 170.645624][ T24] ret_from_fork_asm = (arch/x86/entry/entry_64.S:245) [ 170.645631][ T24] [ 170.645633][ T24] [ 170.657540][ T24] Freed by task 0 on cpu 1 at 165.626544s: [ 170.657945][ T24] kasan_save_track (mm/kasan/common.c:57 = mm/kasan/common.c:78) [ 170.658274][ T24] kasan_save_free_info (mm/kasan/generic.c:584) [ 170.658632][ T24] __kasan_slab_free (mm/kasan/common.c:253 = mm/kasan/common.c:285) [ 170.658965][ T24] __rcu_free_sheaf_prepare = (./include/linux/kasan.h:235 mm/slub.c:2689 mm/slub.c:2940) [ 170.659363][ T24] rcu_free_sheaf (mm/slub.c:5850) [ 170.659693][ T24] rcu_core (kernel/rcu/tree.c:2617 = kernel/rcu/tree.c:2869) [ 170.659997][ T24] handle_softirqs (kernel/softirq.c:622) [ 170.660335][ T24] __irq_exit_rcu (kernel/softirq.c:656 = kernel/softirq.c:496 kernel/softirq.c:735) [ 170.660657][ T24] sysvec_apic_timer_interrupt = (arch/x86/kernel/apic/apic.c:1061 arch/x86/kernel/apic/apic.c:1061) [ 170.661058][ T24] asm_sysvec_apic_timer_interrupt = (./arch/x86/include/asm/idtentry.h:697) [ 170.661480][ T24] [ 170.661645][ T24] The buggy address belongs to the object at = ffff8881092e1000 [ 170.661645][ T24] which belongs to the cache kmalloc-2k of size = 2048 [ 170.662610][ T24] The buggy address is located 0 bytes inside of [ 170.662610][ T24] freed 2048-byte region [ffff8881092e1000, = ffff8881092e1800) Best, Shuangpeng