From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga05-in.huawei.com (szxga05-in.huawei.com [45.249.212.191]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2F65718991E; Sun, 26 Jan 2025 03:45:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.191 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737863116; cv=none; b=ZEjUqZFFYF52BObAwMKCRHw1uHfw4tGkO0nyy/O8MMzIQ5vlC2ai6X45lmSkHP/HiJ/ZTsEMd6HbfC9WIVSHbQbOidzwGNHFoSRQwtKxVNKuHh1U43KQKHbxUEZFysx+dsMfGq2JNFDxxpVD70Rn60gBITFYHgB7kWGzfsqmcpQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737863116; c=relaxed/simple; bh=Mp2HSW7ScroK20xtHp0zTEtQadQgYfzLOtqrggvOstM=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=BdK1HbbP4TeZf5AeRwW3oW8dEVMebPKsKE4F5WEFlGM+8iHpfqS3f8BOQhJkNCQYw3WmANc2hFz13WDEEAipS6rl1Ww3yCYPwJ8SycHrfF/0Gb+VynO3WKKQ6nwCfwdhbdzwwti1RVnyrcSUqWMetDGzeYITDz6MJ22sa+JUJHI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.191 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.88.214]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4YgcmP6F1Fz1l06N; Sun, 26 Jan 2025 11:41:41 +0800 (CST) Received: from kwepemg500017.china.huawei.com (unknown [7.202.181.81]) by mail.maildlp.com (Postfix) with ESMTPS id 95F361A016C; Sun, 26 Jan 2025 11:45:05 +0800 (CST) Received: from [10.174.179.155] (10.174.179.155) by kwepemg500017.china.huawei.com (7.202.181.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Sun, 26 Jan 2025 11:45:04 +0800 Message-ID: Date: Sun, 26 Jan 2025 11:45:03 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: =?UTF-8?B?TW96aWxsYSBUaHVuZGVyYmlyZCDmtYvor5XniYg=?= Subject: Re: [PATCH] nfsd: set acl_access/acl_default after getting successful To: "zhangjian (CG)" , Li Lingfeng , , , , , , , , , , CC: , , , References: <20241107014705.2509463-1-lilingfeng@huaweicloud.com> <93fd0f1c-812f-4393-ad73-4d07ecebf979@huawei.com> From: Li Lingfeng In-Reply-To: <93fd0f1c-812f-4393-ad73-4d07ecebf979@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemg500017.china.huawei.com (7.202.181.81) 在 2024/11/28 9:17, zhangjian (CG) 写道: > there is one case when disk error cause get_inode_acl(inode, > ACL_TYPE_DEFAULT) return EIO, > resp->acl_access will not be null. > posix_acl_release(resp->acl_default) will trigger this warning. > Yes, in the problematic scenario, resp->acl_access would not be NULL. The memory pointed to by resp->acl_access would be freed and then accessed again, thereby triggering the issue. > >> If getting acl_default fails, acl_access and acl_default will be >> released >> simultaneously. However, acl_access will still retain a pointer pointing >> to the released posix_acl, which will trigger a WARNING in >> nfs3svc_release_getacl like this: >> >> ------------[ cut here ]------------ >> refcount_t: underflow; use-after-free. >> WARNING: CPU: 26 PID: 3199 at lib/refcount.c:28 >> refcount_warn_saturate+0xb5/0x170 >> Modules linked in: >> CPU: 26 UID: 0 PID: 3199 Comm: nfsd Not tainted >> 6.12.0-rc6-00079-g04ae226af01f-dirty #8 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS >> 1.16.1-2.fc37 04/01/2014 >> RIP: 0010:refcount_warn_saturate+0xb5/0x170 >> Code: cc cc 0f b6 1d b3 20 a5 03 80 fb 01 0f 87 65 48 d8 00 83 e3 01 75 >> e4 48 c7 c7 c0 3b 9b 85 c6 05 97 20 a5 03 01 e8 fb 3e 30 ff <0f> 0b eb >> cd 0f b6 1d 8a3 >> RSP: 0018:ffffc90008637cd8 EFLAGS: 00010282 >> RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff83904fde >> RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff88871ed36380 >> RBP: ffff888158beeb40 R08: 0000000000000001 R09: fffff520010c6f56 >> R10: ffffc90008637ab7 R11: 0000000000000001 R12: 0000000000000001 >> R13: ffff888140e77400 R14: ffff888140e77408 R15: ffffffff858b42c0 >> FS:  0000000000000000(0000) GS:ffff88871ed00000(0000) >> knlGS:0000000000000000 >> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 0000562384d32158 CR3: 000000055cc6a000 CR4: 00000000000006f0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> Call Trace: >>   >>   ? refcount_warn_saturate+0xb5/0x170 >>   ? __warn+0xa5/0x140 >>   ? refcount_warn_saturate+0xb5/0x170 >>   ? report_bug+0x1b1/0x1e0 >>   ? handle_bug+0x53/0xa0 >>   ? exc_invalid_op+0x17/0x40 >>   ? asm_exc_invalid_op+0x1a/0x20 >>   ? tick_nohz_tick_stopped+0x1e/0x40 >>   ? refcount_warn_saturate+0xb5/0x170 >>   ? refcount_warn_saturate+0xb5/0x170 >>   nfs3svc_release_getacl+0xc9/0xe0 >>   svc_process_common+0x5db/0xb60 >>   ? __pfx_svc_process_common+0x10/0x10 >>   ? __rcu_read_unlock+0x69/0xa0 >>   ? __pfx_nfsd_dispatch+0x10/0x10 >>   ? svc_xprt_received+0xa1/0x120 >>   ? xdr_init_decode+0x11d/0x190 >>   svc_process+0x2a7/0x330 >>   svc_handle_xprt+0x69d/0x940 >>   svc_recv+0x180/0x2d0 >>   nfsd+0x168/0x200 >>   ? __pfx_nfsd+0x10/0x10 >>   kthread+0x1a2/0x1e0 >>   ? kthread+0xf4/0x1e0 >>   ? __pfx_kthread+0x10/0x10 >>   ret_from_fork+0x34/0x60 >>   ? __pfx_kthread+0x10/0x10 >>   ret_from_fork_asm+0x1a/0x30 >>   >> Kernel panic - not syncing: kernel: panic_on_warn set ... >> >> Clear acl_access/acl_default first and set both of them only when both >> ACLs are successfully obtained. >> >> Fixes: a257cdd0e217 ("[PATCH] NFSD: Add server support for NFSv3 ACLs.") >> Signed-off-by: Li Lingfeng >> --- >>   fs/nfsd/nfs3acl.c | 14 ++++++++------ >>   1 file changed, 8 insertions(+), 6 deletions(-) >> >> diff --git a/fs/nfsd/nfs3acl.c b/fs/nfsd/nfs3acl.c >> index 5e34e98db969..17579a032a5b 100644 >> --- a/fs/nfsd/nfs3acl.c >> +++ b/fs/nfsd/nfs3acl.c >> @@ -29,10 +29,12 @@ static __be32 nfsd3_proc_getacl(struct svc_rqst >> *rqstp) >>   { >>       struct nfsd3_getaclargs *argp = rqstp->rq_argp; >>       struct nfsd3_getaclres *resp = rqstp->rq_resp; >> -    struct posix_acl *acl; >> +    struct posix_acl *acl = NULL, *dacl = NULL; >>       struct inode *inode; >>       svc_fh *fh; >>   +    resp->acl_access = NULL; >> +    resp->acl_default = NULL; >>       fh = fh_copy(&resp->fh, &argp->fh); >>       resp->status = fh_verify(rqstp, &resp->fh, 0, NFSD_MAY_NOP); >>       if (resp->status != nfs_ok) >> @@ -56,19 +58,19 @@ static __be32 nfsd3_proc_getacl(struct svc_rqst >> *rqstp) >>               resp->status = nfserrno(PTR_ERR(acl)); >>               goto fail; >>           } >> -        resp->acl_access = acl; >>       } >>       if (resp->mask & (NFS_DFACL|NFS_DFACLCNT)) { >>           /* Check how Solaris handles requests for the Default ACL >>              of a non-directory! */ >> -        acl = get_inode_acl(inode, ACL_TYPE_DEFAULT); >> -        if (IS_ERR(acl)) { >> -            resp->status = nfserrno(PTR_ERR(acl)); >> +        dacl = get_inode_acl(inode, ACL_TYPE_DEFAULT); >> +        if (IS_ERR(dacl)) { >> +            resp->status = nfserrno(PTR_ERR(dacl)); >>               goto fail; >>           } >> -        resp->acl_default = acl; >>       } >>   +    resp->acl_access = acl; >> +    resp->acl_default = dacl; >>       /* resp->acl_{access,default} are released in >> nfs3svc_release_getacl. */ >>   out: >>       return rpc_success;