| Message ID | 20161029183113.12077.81804.stgit@klimt.1015granger.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, 2016-10-29 at 14:31 -0400, Chuck Lever wrote: > When I push NFSv4.1 / RDMA hard, (xfstests generic/089, for example), > I get this crash on the server: > > Oct 28 22:04:30 klimt kernel: general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC > Oct 28 22:04:30 klimt kernel: Modules linked in: cts rpcsec_gss_krb5 iTCO_wdt iTCO_vendor_support sb_edac edac_core x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm btrfs irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd xor pcspkr raid6_pq i2c_i801 i2c_smbus lpc_ich mfd_core sg mei_me mei ioatdma shpchp wmi ipmi_si ipmi_msghandler rpcrdma ib_ipoib rdma_ucm acpi_power_meter acpi_pad ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c mlx4_ib mlx4_en ib_core sr_mod cdrom sd_mod ast drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm crc32c_intel igb ahci libahci ptp mlx4_core pps_core dca libata i2c_algo_bit i2c_core dm_mirror dm_region_hash dm_log dm_mod > Oct 28 22:04:30 klimt kernel: CPU: 7 PID: 1558 Comm: nfsd Not tainted 4.9.0-rc2-00005-g82cd754 #8 > Oct 28 22:04:30 klimt kernel: Hardware name: Supermicro Super Server/X10SRL-F, BIOS 1.0c 09/09/2015 > Oct 28 22:04:30 klimt kernel: task: ffff880835c3a100 task.stack: ffff8808420d8000 > Oct 28 22:04:30 klimt kernel: RIP: 0010:[<ffffffffa05a759f>] [<ffffffffa05a759f>] release_lock_stateid+0x1f/0x60 [nfsd] > Oct 28 22:04:30 klimt kernel: RSP: 0018:ffff8808420dbce0 EFLAGS: 00010246 > Oct 28 22:04:30 klimt kernel: RAX: ffff88084e6660f0 RBX: ffff88084e667020 RCX: 0000000000000000 > Oct 28 22:04:30 klimt kernel: RDX: 0000000000000007 RSI: 0000000000000000 RDI: ffff88084e667020 > Oct 28 22:04:30 klimt kernel: RBP: ffff8808420dbcf8 R08: 0000000000000001 R09: 0000000000000000 > Oct 28 22:04:30 klimt kernel: R10: ffff880835c3a100 R11: ffff880835c3aca8 R12: 6b6b6b6b6b6b6b6b > Oct 28 22:04:30 klimt kernel: R13: ffff88084e6670d8 R14: ffff880835f546f0 R15: ffff880835f1c548 > Oct 28 22:04:30 klimt kernel: FS: 0000000000000000(0000) GS:ffff88087bdc0000(0000) knlGS:0000000000000000 > Oct 28 22:04:30 klimt kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > Oct 28 22:04:30 klimt kernel: CR2: 00007ff020389000 CR3: 0000000001c06000 CR4: 00000000001406e0 > Oct 28 22:04:30 klimt kernel: Stack: > Oct 28 22:04:30 klimt kernel: ffff88084e667020 0000000000000000 ffff88084e6670d8 ffff8808420dbd20 > Oct 28 22:04:30 klimt kernel: ffffffffa05ac80d ffff880835f54548 ffff88084e640008 ffff880835f545b0 > Oct 28 22:04:30 klimt kernel: ffff8808420dbd70 ffffffffa059803d ffff880835f1c768 0000000000000870 > Oct 28 22:04:30 klimt kernel: Call Trace: > Oct 28 22:04:30 klimt kernel: [<ffffffffa05ac80d>] nfsd4_free_stateid+0xfd/0x1b0 [nfsd] > Oct 28 22:04:30 klimt kernel: [<ffffffffa059803d>] nfsd4_proc_compound+0x40d/0x690 [nfsd] > Oct 28 22:04:30 klimt kernel: [<ffffffffa0583114>] nfsd_dispatch+0xd4/0x1d0 [nfsd] > Oct 28 22:04:30 klimt kernel: [<ffffffffa047bbf9>] svc_process_common+0x3d9/0x700 [sunrpc] > Oct 28 22:04:30 klimt kernel: [<ffffffffa047ca64>] svc_process+0xf4/0x330 [sunrpc] > Oct 28 22:04:30 klimt kernel: [<ffffffffa05827ca>] nfsd+0xfa/0x160 [nfsd] > Oct 28 22:04:30 klimt kernel: [<ffffffffa05826d0>] ? nfsd_destroy+0x170/0x170 [nfsd] > Oct 28 22:04:30 klimt kernel: [<ffffffff810b367b>] kthread+0x10b/0x120 > Oct 28 22:04:30 klimt kernel: [<ffffffff810b3570>] ? kthread_stop+0x280/0x280 > Oct 28 22:04:30 klimt kernel: [<ffffffff8174e8ba>] ret_from_fork+0x2a/0x40 > Oct 28 22:04:30 klimt kernel: Code: c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 55 41 54 53 48 8b 87 b0 00 00 00 48 89 fb 4c 8b a0 98 00 00 00 <49> 8b 44 24 20 48 8d b8 80 03 00 00 e8 10 66 1a e1 48 89 df e8 > Oct 28 22:04:30 klimt kernel: RIP [<ffffffffa05a759f>] release_lock_stateid+0x1f/0x60 [nfsd] > Oct 28 22:04:30 klimt kernel: RSP <ffff8808420dbce0> > Oct 28 22:04:30 klimt kernel: ---[ end trace cf5d0b371973e167 ]--- > > Jeff Layton says: > > > > Hm...now that I look though, this is a little suspicious: > > > > struct nfs4_openowner *oo = openowner(stp->st_openstp->st_stateowner); > > > > I wonder if it's possible for the openstateid to have already been > > destroyed at this point. > > > > We might be better off doing something like this to get the client pointer: > > > > stp->st_stid.sc_client; > > > > ...which should be more direct and less dependent on other stateids > > staying valid. > > With the suggested change, I am no longer able to reproduce the above oops. > > Fix-suggested-by: Jeff Layton <jlayton@redhat.com> > Fixes: 42691398be08 ('nfsd: Fix race between FREE_STATEID and LOCK') > Signed-off-by: Chuck Lever <chuck.lever@oracle.com> > --- > fs/nfsd/nfs4state.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index 9752beb..34b38fc 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -1238,12 +1238,12 @@ static bool unhash_lock_stateid(struct nfs4_ol_stateid *stp) > > static void release_lock_stateid(struct nfs4_ol_stateid *stp) > { > - struct nfs4_openowner *oo = openowner(stp->st_openstp->st_stateowner); > + struct nfs4_client *clp = stp->st_stid.sc_client; > bool unhashed; > > - spin_lock(&oo->oo_owner.so_client->cl_lock); > + spin_lock(&clp->cl_lock); > unhashed = unhash_lock_stateid(stp); > - spin_unlock(&oo->oo_owner.so_client->cl_lock); > + spin_unlock(&clp->cl_lock); > if (unhashed) > nfs4_put_stid(&stp->st_stid); > } > Nice! Can you also change the lockdep assert in unhash_lock_stateid as well? I think we could hit the same crash there. I also wonder whether we ought to just have the lock stateids hold a reference to st_openstp, but I'm not sure whether that would screw up the open stateid refcounting. I'll take a look over the code sometime soon and see whether that makes sense.
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 9752beb..34b38fc 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1238,12 +1238,12 @@ static bool unhash_lock_stateid(struct nfs4_ol_stateid *stp) static void release_lock_stateid(struct nfs4_ol_stateid *stp) { - struct nfs4_openowner *oo = openowner(stp->st_openstp->st_stateowner); + struct nfs4_client *clp = stp->st_stid.sc_client; bool unhashed; - spin_lock(&oo->oo_owner.so_client->cl_lock); + spin_lock(&clp->cl_lock); unhashed = unhash_lock_stateid(stp); - spin_unlock(&oo->oo_owner.so_client->cl_lock); + spin_unlock(&clp->cl_lock); if (unhashed) nfs4_put_stid(&stp->st_stid); }