On Sat, Dec 11, 2021 at 09:58:54AM +0100, Mark Kettenis wrote: > This one may be harmless. The first backtrace is from executing > init(8), which only happens once and happens in a somewhat strange > manner.
This happens in some /usr/src/regress/misc/posixtestsuite test. It needs pkg_add posixtestsuite from ports. conformance/interfaces/mmap/13-1: execution: PASS witness: lock order reversal: 1st 0xfffffd8774d45038 vmmaplk (&map->lock) 2nd 0xfffffd86eaf8dc48 inode (&ip->i_lock) lock order "&ip->i_lock"(rrwlock) -> "&map->lock"(rwlock) first seen at: #0 rw_enter_read+0x38 #1 uvmfault_lookup+0x8a #2 uvm_fault_check+0x32 #3 uvm_fault+0xfc #4 kpageflttrap+0x12b #5 kerntrap+0x91 #6 alltraps_kern_meltdown+0x7b #7 copyout+0x53 #8 ffs_read+0x1f6 #9 VOP_READ+0x41 #10 vn_rdwr+0xa1 #11 vmcmd_map_readvn+0xa6 #12 exec_process_vmcmds+0x84 #13 sys_execve+0x77d #14 start_init+0x29f #15 proc_trampoline+0x1c lock order "&map->lock"(rwlock) -> "&ip->i_lock"(rrwlock) first seen at: #0 rw_enter+0x65 #1 rrw_enter+0x56 #2 VOP_LOCK+0x5b #3 vn_lock+0xad #4 uvn_io+0x1cc #5 uvm_pager_put+0xe6 #6 uvn_flush+0x250 #7 uvm_map_clean+0x1ff #8 syscall+0x374 #9 Xsyscall+0x128 conformance/interfaces/mmap/14-1: execution: PASS > so this is accessing a vnd whichis backed by a file on NFS. Not > terribly surprised that this causes issues. I think: > > > lock order "&map->lock"(rwlock) -> "&np->n_lock"(rrwlock) first seen at: > > is the "right" lock order. Unfortunately data for the "wrong" order > is missing... It can be reproduced by /usr/src/regress/sys/ffs/nfs . There I have a diskimage file on ffs. It is mounted via vnd. This file system acts as NFS server. From there it is mounted via 127.0.0.1 as NFS client on the same machine. On top of that the file system test suite is running. /usr/src/regress/sys/ffs/nfs/../tests/chflags/12.t: "chflags returns EROFS if the named file resides on a read-only file system" Running test #0... okay. witness: lock order reversal: 1st 0xfffffd86f37b7768 vmmaplk (&map->lock) 2nd 0xffff800022c19080 nfsnode (&np->n_lock) lock order data w2 -> w1 missing lock order "&map->lock"(rwlock) -> "&np->n_lock"(rrwlock) first seen at: #0 rw_enter+0x65 #1 rrw_enter+0x56 #2 VOP_LOCK+0x5b #3 vn_lock+0xad #4 vn_rdwr+0x7f #5 vndstrategy+0x2e6 #6 physio+0x227 #7 spec_write+0x95 #8 VOP_WRITE+0x41 #9 vn_write+0xfc #10 dofilewritev+0x14d #11 sys_pwrite+0x5c #12 syscall+0x374 #13 Xsyscall+0x128 Running test #1... okay. Running test #2... okay. Next I will tests visa's witness diff.
