Hi all, It's still reproducible on the latest next-20210107 tree with below reproducer. Reverting this fscache update makes the panic gone. 574146fe263a Merge branch 'fscache-next' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git Thanks, Murphy On Wed, Dec 22, 2021 at 10:16:44AM +0800, Murphy Zhou wrote: > A bit late. > > Try this: > > rm -rf cthon04 > git clone git://git.linux-nfs.org/projects/steved/cthon04.git > pushd cthon04 > make clean || exit > make FSTYPE=cifs >cthon04-build.log 2>&1 || exit > popd > > rm -fr /tmp/connectathon > mkdir -p /tmp/connectathon > chmod 1777 /tmp/connectathon > chcon -t samba_share_t /tmp/connectathon > cat > /etc/samba/smb.conf <<EOF > [global] > workgroup = EXAMPLE > unix extensions = no > ea support = Yes > min protocol = NT1 > > [testuser] > comment = testuser unix extensions off > path = /tmp/connectathon > read only = No > #acl check permissions = No > #acl map full control = No > EOF > echo -e 'redhat\nredhat' | smbpasswd -s -a root > service smb restart > sleep 5 > > pushd cthon04 > smbclient -L //$(hostname)/testuser -N > echo "y\n" | ./server -o > actimeo=0,user=root,password=redhat,domain=EXAMPLE,file_mode=0777,rw,noauto > -C -a -f -p testuser -m /mnt/connectathon $(hostname) -b > popd > > > On Sat, Dec 11, 2021 at 11:33 AM Shyam Prasad N <nspmangalore@xxxxxxxxx> wrote: > > > > > > > > On Fri, Dec 10, 2021 at 11:37 AM Murphy Zhou <jencce.kernel@xxxxxxxxx> wrote: > >> > >> The patch can't be applied on the 1208 tree and does not fix the issue > >> on the 1207 tree. > >> > > Hi Murphy, > > > > Which is the git repo and branch that you're using? Is it reproducible consistently? > > And is it a ksmbd server? Or samba server? Can you share the conf file for that as well? > > I'm unable to repro this issue. > > > > Regards, > > Shyam > > > >> On Thu, Dec 9, 2021 at 7:05 PM Murphy Zhou <jencce.kernel@xxxxxxxxx> wrote: > >> > > >> > Test is running. > >> > > >> > And the kernel config is attached. > >> > > >> > Thanks for looking into this! > >> > > >> > On Thu, Dec 9, 2021 at 6:53 PM Shyam Prasad N <nspmangalore@xxxxxxxxx> wrote: > >> > > > >> > > On Thu, Dec 9, 2021 at 3:06 PM Shyam Prasad N <nspmangalore@xxxxxxxxx> wrote: > >> > > > > >> > > > On Thu, Dec 9, 2021 at 2:40 PM Shyam Prasad N <nspmangalore@xxxxxxxxx> wrote: > >> > > > > > >> > > > > Hi Murphy, > >> > > > > > >> > > > > Can you please share the kernel config file used for this test? > >> > > > > Is cachefilesd configured on this test setup? > >> > > > > > >> > > > > Regards, > >> > > > > Shyam > >> > > > > > >> > > > > On Wed, Dec 8, 2021 at 2:57 PM Murphy Zhou <jencce.kernel@xxxxxxxxx> wrote: > >> > > > > > > >> > > > > > Hi, > >> > > > > > > >> > > > > > A connectathon test triggers panic like below. The server is a smb > >> > > > > > share on the same server with the test client. > >> > > > > > > >> > > > > > > >> > > > > > [ 594.061343] Key type cifs.spnego registered > >> > > > > > [ 594.082337] Key type cifs.idmap registered > >> > > > > > [ 594.104961] CIFS: No dialect specified on mount. Default has > >> > > > > > changed to a more secure dialect, SMB2.1 or later (e.g. SMB3.1.1), > >> > > > > > from CIFS (SMB1). To use the less secure SMB1 dialect to access old > >> > > > > > servers which do not support SMB3.1.1 (or even SMB3 or SMB2.1) specify > >> > > > > > vers=1.0 on mount. > >> > > > > > [ 594.223460] CIFS: Attempting to mount \\hp-dl380pg8\testuser > >> > > > > > [ 594.287771] BUG: kernel NULL pointer dereference, address: 0000000000000000 > >> > > > > > [ 594.319712] #PF: supervisor write access in kernel mode > >> > > > > > [ 594.343627] #PF: error_code(0x0002) - not-present page > >> > > > > > [ 594.366791] PGD 0 P4D 0 > >> > > > > > [ 594.378172] Oops: 0002 [#1] PREEMPT SMP PTI > >> > > > > > [ 594.397047] CPU: 0 PID: 52196 Comm: mount.cifs Kdump: loaded > >> > > > > > Tainted: G I 5.16.0-rc4-next-20211206 #1 > >> > > > > > [ 594.445144] Hardware name: HP ProLiant DL380p Gen8, BIOS P70 08/02/2014 > >> > > > > > [ 594.475201] RIP: 0010:cifs_fscache_get_inode_cookie+0x2f/0xb0 [cifs] > >> > > > > > [ 594.503934] Code: 53 48 89 fb 48 83 ec 20 65 48 8b 04 25 28 00 00 > >> > > > > > 00 48 89 44 24 18 48 8b 47 28 48 8b b8 88 03 00 00 e8 35 c6 fa ff 48 > >> > > > > > 8b 53 68 <48> 89 14 25 00 00 00 00 48 8b 53 70 89 14 25 10 00 00 00 48 > >> > > > > > 8b 53 > >> > > > > > [ 594.590004] RSP: 0018:ffffb93c4998fc10 EFLAGS: 00010282 > >> > > > > > [ 594.614861] RAX: ffff970743ab5000 RBX: ffff970411193168 RCX: 0000000000000000 > >> > > > > > [ 594.650920] RDX: 0000000061b01059 RSI: 00000000000041ed RDI: ffff970453924780 > >> > > > > > [ 594.686189] RBP: ffffb93c4998fce8 R08: ffff970411193168 R09: ffff970743ab1548 > >> > > > > > [ 594.718776] R10: 000000009f8bdc24 R11: 000000009053e561 R12: 000000000e1c25d9 > >> > > > > > [ 594.750925] R13: ffff970411193168 R14: ffff970743ab1000 R15: ffff970743ab5000 > >> > > > > > [ 594.783532] FS: 00007f2037080780(0000) GS:ffff97072f600000(0000) > >> > > > > > knlGS:0000000000000000 > >> > > > > > [ 594.820129] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > >> > > > > > [ 594.846183] CR2: 0000000000000000 CR3: 0000000141820006 CR4: 00000000001706f0 > >> > > > > > [ 594.878376] Call Trace: > >> > > > > > [ 594.889469] <TASK> > >> > > > > > [ 594.898870] cifs_iget+0x14b/0x160 [cifs] > >> > > > > > [ 594.917781] cifs_get_inode_info+0x430/0x750 [cifs] > >> > > > > > [ 594.941267] ? __d_instantiate+0x34/0xf0 > >> > > > > > [ 594.960012] ? _raw_spin_unlock+0x16/0x30 > >> > > > > > [ 594.978111] ? d_instantiate+0x3e/0x60 > >> > > > > > [ 594.994982] cifs_root_iget+0x33b/0x4b0 [cifs] > >> > > > > > [ 595.015099] cifs_read_super+0x125/0x200 [cifs] > >> > > > > > [ 595.035596] cifs_smb3_do_mount+0x224/0x330 [cifs] > >> > > > > > [ 595.057009] smb3_get_tree+0x2d/0x50 [cifs] > >> > > > > > [ 595.076065] vfs_get_tree+0x25/0xb0 > >> > > > > > [ 595.092562] do_new_mount+0x176/0x310 > >> > > > > > [ 595.110929] __x64_sys_mount+0x103/0x140 > >> > > > > > [ 595.130439] do_syscall_64+0x3b/0x90 > >> > > > > > [ 595.147929] entry_SYSCALL_64_after_hwframe+0x44/0xae > >> > > > > > [ 595.172646] RIP: 0033:0x7f2037195c4e > >> > > > > > [ 595.188703] Code: 48 8b 0d dd 71 0e 00 f7 d8 64 89 01 48 83 c8 ff > >> > > > > > c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 a5 00 00 > >> > > > > > 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d aa 71 0e 00 f7 d8 64 89 > >> > > > > > 01 48 > >> > > > > > [ 595.273644] RSP: 002b:00007fff27645a38 EFLAGS: 00000202 ORIG_RAX: > >> > > > > > 00000000000000a5 > >> > > > > > [ 595.307790] RAX: ffffffffffffffda RBX: 000055690a1bb910 RCX: 00007f2037195c4e > >> > > > > > [ 595.340187] RDX: 0000556908d5946b RSI: 0000556908d594b6 RDI: 00007fff27647fbe > >> > > > > > [ 595.372419] RBP: 000055690a1bb8f0 R08: 000055690a1bb910 R09: 0000000000000077 > >> > > > > > [ 595.404633] R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff27647fb3 > >> > > > > > [ 595.436882] R13: 00007f203729d000 R14: 00007f203729f70e R15: 00007fff27647fbe > >> > > > > > [ 595.468980] </TASK> > >> > > > > > [ 595.478769] Modules linked in: cifs cifs_arc4 cifs_md4 loop nfsv3 > >> > > > > > rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache netfs rpcrdma rdma_cm > >> > > > > > iw_cm ib_cm ib_core nfsd auth_rpcgss nfs_acl lockd grace rfkill sunrpc > >> > > > > > intel_rapl_msr intel_rapl_common sb_edac x86_pkg_temp_thermal > >> > > > > > intel_powerclamp mgag200 coretemp i2c_algo_bit kvm_intel > >> > > > > > drm_shmem_helper drm_kms_helper ipmi_ssif iTCO_wdt kvm > >> > > > > > iTCO_vendor_support acpi_ipmi syscopyarea irqbypass sysfillrect > >> > > > > > ipmi_si rapl intel_cstate ioatdma ipmi_devintf sysimgblt intel_uncore > >> > > > > > fb_sys_fops cec lpc_ich ipmi_msghandler acpi_power_meter pcspkr dca > >> > > > > > hpilo drm fuse xfs libcrc32c sr_mod cdrom sd_mod ata_generic t10_pi sg > >> > > > > > ata_piix crct10dif_pclmul crc32_pclmul crc32c_intel libata serio_raw > >> > > > > > tg3 ghash_clmulni_intel hpsa hpwdt scsi_transport_sas dm_mirror > >> > > > > > dm_region_hash dm_log dm_mod > >> > > > > > [ 595.821049] CR2: 0000000000000000 > >> > > > > > >> > > > > > >> > > > > > >> > > > > -- > >> > > > > Regards, > >> > > > > Shyam > >> > > > > >> > > > This does not repro against a Windows server. > >> > > > My suspicion is that the recent change of location of > >> > > > cifs_fscache_get_super_cookie to cifs_root_iget caused this. We maybe > >> > > > trying to initialize the inode cookie when the super cookie is yet to > >> > > > be initialized. > >> > > > > >> > > > The bigger point here is that there seems to be a circular dependency: > >> > > > We need tcon->resource_id to setup the super cookie. This is populated > >> > > > using inode number of root directory. Getting this inode number needs > >> > > > opening of the root dir. Open causes inode cookie to be initialized, > >> > > > which trips when it sees that the super cookie is still NULL. > >> > > > > >> > > > Steve: Do you agree with this assessment? How do we fix this? Can we > >> > > > use some other value for resource_id, and not have to rely on the root > >> > > > inode number? How about tcon->tid? Or a combination of tcon->tid and > >> > > > ses->Suid? > >> > > > > >> > > > -- > >> > > > Regards, > >> > > > Shyam > >> > > > >> > > Hi Murphy, > >> > > > >> > > Will you be able to test out with this patch as a possible fix for this issue? > >> > > > >> > > -- > >> > > Regards, > >> > > Shyam > > > > > > > > -- > > Regards, > > Shyam -- Murphy -- Linux-cachefs mailing list Linux-cachefs@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/linux-cachefs
