Hi, We have a cluster of machines where we're observing file accesses hanging over NFS. The clients showing the problems are Fedora and SUSE distros with the 5.6.11 kernel, e.g.: Linux version 5.6.11-1-default (geeko@buildhost) (gcc version 9.3.1 20200406 [revision 6db837a5288ee3ca5ec504fbd5a765817e556ac2] (SUSE Linux)) #1 SMP Wed May 6 10:42:09 UTC 2020 (91c024a) In the example below we see a git clone hang, its having trouble reading a .pack file off the NFS share, the git process is in D state. I've included part of dmesg below with sysrq-w output. Mount options: rw,relatime,vers=4.1,rsize=131072,wsize=131072,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,local_lock=none mountstats shows: READ: 632014263 ops (62%) 629809108 errors (99%) TEST_STATEID: 363257078 ops (36%) 363257078 errors (100%) which is a clue on what is happening. I grabbed some data with tcpdump and it shows the READ getting NFS4ERR_BAD_STATEID, there is then a TEST_STATEID which gets NFS4ERR_NOTSUPP. This repeats infinitely in a loop. The server is FreeNAS11.3 which does not have: https://github.com/HardenedBSD/hardenedBSD-stable/commit/63f6f19b0756b18f2e68d82cbe037f21f9a8c500 applied so it will return NFS4ERR_NOTSUPP to TEST_STATEID. I think something may be needed to stop Linux getting into an infinite loop with this, regardless of whether the spec says TEST_STATEID can get a NFS4ERR_NOTSUPP or not? I freely admit I know little about much of this so I'm open to pointers. If we did remount as 4.0 we probably wouldn't see the issue as it would avoid the TEST_STATEID code. Cheers, Richard [249239.124271] NFS: nfs4_reclaim_open_state: unhandled error -524 [249239.124722] NFSv4: state recovery failed for open file git2/github.com.rpm-software-management.dnf.git.lock, error = -524 [249239.124723] NFSv4: state recovery failed for open file git2/github.com.rpm-software-management.dnf.git.lock, error = -524 [249239.124724] NFSv4: state recovery failed for open file git2/github.com.rpm-software-management.dnf.git.lock, error = -524 [249244.947749] NFS: __nfs4_reclaim_open_state: Lock reclaim failed! [249244.964169] NFS: nfs4_reclaim_open_state: unhandled error -524 [249244.964646] NFSv4: state recovery failed for open file git2/github.com.rpm-software-management.dnf.git.lock, error = -524 [249244.964648] NFSv4: state recovery failed for open file git2/github.com.rpm-software-management.dnf.git.lock, error = -524 [376912.912171] NFS: __nfs4_reclaim_open_state: Lock reclaim failed! [376913.215654] NFS: __nfs4_reclaim_open_state: Lock reclaim failed! [408558.690581] sysrq: Show Blocked State [408558.690630] task PC stack pid father [408558.692490] git D 0 41178 41159 0x00000004 [408558.692494] Call Trace: [408558.692506] ? __schedule+0x2d8/0x760 [408558.692512] ? blk_finish_plug+0x21/0x2e [408558.692516] ? read_pages+0x87/0x1a0 [408558.692519] schedule+0x4a/0xb0 [408558.692522] io_schedule+0x12/0x40 [408558.692528] __lock_page_killable+0x131/0x250 [408558.692532] ? file_fdatawait_range+0x20/0x20 [408558.692536] filemap_fault+0x69e/0x9d0 [408558.692540] ? alloc_set_pte+0x118/0x660 [408558.692546] ? __alloc_pages_nodemask+0x166/0x300 [408558.692552] ? xas_load+0x9/0x80 [408558.692556] ? xas_find+0x177/0x1c0 [408558.692559] ? filemap_map_pages+0x8b/0x380 [408558.692562] __do_fault+0x36/0xd0 [408558.692565] do_fault+0x246/0x520 [408558.692569] __handle_mm_fault+0x5d5/0x820 [408558.692573] handle_mm_fault+0xc4/0x1f0 [408558.692579] do_user_addr_fault+0x1f9/0x450 [408558.692585] page_fault+0x3e/0x50 [408558.692589] RIP: 0033:0x561301328dd1 [408558.692596] Code: Bad RIP value. [408558.692597] RSP: 002b:00007fff69c81e10 EFLAGS: 00010202 [408558.692600] RAX: 00007fc2165118a2 RBX: 00007fff69c81ec8 RCX: 00007fff69c81ec0 [408558.692601] RDX: 00007fff69c81e2c RSI: 00000000001bd2a9 RDI: 00007fc2165118a2 [408558.692602] RBP: 0000561303310ab0 R08: 000000000014e8a2 R09: 0000000000000075 [408558.692604] R10: 00005613014843e0 R11: 0000000000000004 R12: 00007fff69c81ec0 [408558.692605] R13: 0000000000000040 R14: 00007fff69c81f00 R15: 00007fff69c81ed0
