path: root/fs
diff options
authorJeff Layton <jlayton@poochiereds.net>2015-05-12 15:48:10 -0400
committerTrond Myklebust <trond.myklebust@primarydata.com>2015-05-13 14:56:06 -0400
commitfeaff8e5b2cfc3eae02cf65db7a400b0b9ffc596 (patch)
treedc2973377ca4d9706da6e0fe1335c06c292de054 /fs
parent6b19687563fa6f385ac314afa30b7579e8c3174c (diff)
nfs: take extra reference to fl->fl_file when running a setlk
We had a report of a crash while stress testing the NFS client: BUG: unable to handle kernel NULL pointer dereference at 0000000000000150 IP: [<ffffffff8127b698>] locks_get_lock_context+0x8/0x90 PGD 0 Oops: 0000 [#1] SMP Modules linked in: rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ebtable_nat ebtable_filter ebtable_broute bridge stp llc ebtables ip6table_security ip6table_mangle ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_raw ip6table_filter ip6_tables iptable_security iptable_mangle iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_raw coretemp crct10dif_pclmul ppdev crc32_pclmul crc32c_intel ghash_clmulni_intel vmw_balloon serio_raw vmw_vmci i2c_piix4 shpchp parport_pc acpi_cpufreq parport nfsd auth_rpcgss nfs_acl lockd grace sunrpc vmwgfx drm_kms_helper ttm drm mptspi scsi_transport_spi mptscsih mptbase e1000 ata_generic pata_acpi CPU: 1 PID: 399 Comm: kworker/1:1H Not tainted 4.1.0-0.rc1.git0.1.fc23.x86_64 #1 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/30/2013 Workqueue: rpciod rpc_async_schedule [sunrpc] task: ffff880036aea7c0 ti: ffff8800791f4000 task.ti: ffff8800791f4000 RIP: 0010:[<ffffffff8127b698>] [<ffffffff8127b698>] locks_get_lock_context+0x8/0x90 RSP: 0018:ffff8800791f7c00 EFLAGS: 00010293 RAX: ffff8800791f7c40 RBX: ffff88001f2ad8c0 RCX: ffffe8ffffc80305 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff8800791f7c88 R08: ffff88007fc971d8 R09: 279656d600000000 R10: 0000034a01000000 R11: 279656d600000000 R12: ffff88001f2ad918 R13: ffff88001f2ad8c0 R14: 0000000000000000 R15: 0000000100e73040 FS: 0000000000000000(0000) GS:ffff88007fc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000150 CR3: 0000000001c0b000 CR4: 00000000000407e0 Stack: ffffffff8127c5b0 ffff8800791f7c18 ffffffffa0171e29 ffff8800791f7c58 ffffffffa0171ef8 ffff8800791f7c78 0000000000000246 ffff88001ea0ba00 ffff8800791f7c40 ffff8800791f7c40 00000000ff5d86a3 ffff8800791f7ca8 Call Trace: [<ffffffff8127c5b0>] ? __posix_lock_file+0x40/0x760 [<ffffffffa0171e29>] ? rpc_make_runnable+0x99/0xa0 [sunrpc] [<ffffffffa0171ef8>] ? rpc_wake_up_task_queue_locked.part.35+0xc8/0x250 [sunrpc] [<ffffffff8127cd3a>] posix_lock_file_wait+0x4a/0x120 [<ffffffffa03e4f12>] ? nfs41_wake_and_assign_slot+0x32/0x40 [nfsv4] [<ffffffffa03bf108>] ? nfs41_sequence_done+0xd8/0x2d0 [nfsv4] [<ffffffffa03c116d>] do_vfs_lock+0x2d/0x30 [nfsv4] [<ffffffffa03c251d>] nfs4_lock_done+0x1ad/0x210 [nfsv4] [<ffffffffa0171a30>] ? __rpc_sleep_on_priority+0x390/0x390 [sunrpc] [<ffffffffa0171a30>] ? __rpc_sleep_on_priority+0x390/0x390 [sunrpc] [<ffffffffa0171a5c>] rpc_exit_task+0x2c/0xa0 [sunrpc] [<ffffffffa0167450>] ? call_refreshresult+0x150/0x150 [sunrpc] [<ffffffffa0172640>] __rpc_execute+0x90/0x460 [sunrpc] [<ffffffffa0172a25>] rpc_async_schedule+0x15/0x20 [sunrpc] [<ffffffff810baa1b>] process_one_work+0x1bb/0x410 [<ffffffff810bacc3>] worker_thread+0x53/0x480 [<ffffffff810bac70>] ? process_one_work+0x410/0x410 [<ffffffff810bac70>] ? process_one_work+0x410/0x410 [<ffffffff810c0b38>] kthread+0xd8/0xf0 [<ffffffff810c0a60>] ? kthread_worker_fn+0x180/0x180 [<ffffffff817a1aa2>] ret_from_fork+0x42/0x70 [<ffffffff810c0a60>] ? kthread_worker_fn+0x180/0x180 Jean says: "Running locktests with a large number of iterations resulted in a client crash. The test run took a while and hasn't finished after close to 2 hours. The crash happened right after I gave up and killed the test (after 107m) with Ctrl+C." The crash happened because a NULL inode pointer got passed into locks_get_lock_context. The call chain indicates that file_inode(filp) returned NULL, which means that f_inode was NULL. Since that's zeroed out in __fput, that suggests that this filp pointer outlived the last reference. Looking at the code, that seems possible. We copy the struct file_lock that's passed in, but if the task is signalled at an inopportune time we can end up trying to use that file_lock in rpciod context after the process that requested it has already returned (and possibly put its filp reference). Fix this by taking an extra reference to the filp when we allocate the lock info, and put it in nfs4_lock_release. Reported-by: Jean Spector <jean@primarydata.com> Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs')
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 45b35b9b1e36..55e1e3af23a3 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -38,6 +38,7 @@
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/errno.h>
+#include <linux/file.h>
#include <linux/string.h>
#include <linux/ratelimit.h>
#include <linux/printk.h>
@@ -5604,6 +5605,7 @@ static struct nfs4_lockdata *nfs4_alloc_lockdata(struct file_lock *fl,
p->server = server;
p->ctx = get_nfs_open_context(ctx);
+ get_file(fl->fl_file);
memcpy(&p->fl, fl, sizeof(p->fl));
return p;
@@ -5716,6 +5718,7 @@ static void nfs4_lock_release(void *calldata)
+ fput(data->fl.fl_file);
dprintk("%s: done!\n", __func__);

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