Hi,
We have a remote repo accessed using the 'file:' protocol, mounted over Samba using drvfs into a WSL2 instance of Ubuntu 20.04.
We find a 'git push' waits forever. git version 2.25.1
Over a local LAN this works fine, but over a VPN this fails, hinting at some sort of race condition.
Output from strace hints that git is trying (and failing) to read from a closed file handle.
Final output from strace:
-----------
openat(AT_FDCWD, ".git/objects/ad/065dad4384ae8c81c120c562985078d1f7b34b", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0444, st_size=152, ...}) = 0
mmap(NULL, 152, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f3e0e4af000
close(3) = 0
munmap(0x7f3e0e4af000, 152) = 0
openat(AT_FDCWD, ".git/objects/30/2508dfe5201db6c000ebf17b0c69e3afb31218", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0555, st_size=214, ...}) = 0
mmap(NULL, 214, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f3e0e4af000
close(3) = 0
munmap(0x7f3e0e4af000, 214) = 0
openat(AT_FDCWD, ".git/objects/d2/2323ec2ec40a74fbd519509662254c3cfda206", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0444, st_size=161, ...}) = 0
mmap(NULL, 161, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f3e0e4af000
close(3) = 0
munmap(0x7f3e0e4af000, 161) = 0
access(".git/hooks/pre-push", X_OK) = -1 ENOENT (No such file or directory)
write(4, "00953ea50e3c1f49c33f7dbbb5e3a310"..., 149) = 149
write(4, "0000", 4) = 4
pipe([3, 6]) = 0
fcntl(6, F_GETFD) = 0
fcntl(6, F_SETFD, FD_CLOEXEC) = 0
mmap(NULL, 8392704, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_STACK, -1, 0) = 0x7f3e0d641000
mprotect(0x7f3e0d642000, 8388608, PROT_READ|PROT_WRITE) = 0
clone(child_stack=0x7f3e0de40fb0, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, parent_tid=[12802], tls=0x7f3e0de41700, child_tidptr=0x7f3e0de419d0) = 12802
pipe([7, 8]) = 0
stat("/usr/lib/git-core/git", {st_mode=S_IFREG|0755, st_size=3093072, ...}) = 0
pipe([9, 10]) = 0
rt_sigprocmask(SIG_SETMASK, ~[RTMIN RT_1], [], 8) = 0
clone(child_stack=NULL, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x7f3e0e1dae50) = 12803
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
close(10) = 0
read(9, "", 8) = 0
close(9) = 0
close(7) = 0
close(4) = 0
fcntl(8, F_GETFL) = 0x1 (flags O_WRONLY)
openat(AT_FDCWD, ".git/objects/3e", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4
fstat(4, {st_mode=S_IFDIR|0777, st_size=4096, ...}) = 0
getdents64(4, /* 22 entries */, 32768) = 1328
getdents64(4, /* 0 entries */, 32768) = 0
close(4) = 0
fstat(8, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0
write(8, "^3ea50e3c1f49c33f7dbbb5e3a31017f"..., 83) = 83
close(8) = 0
Enumerating objects: 31, done.ts: 1
Counting objects: 100% (31/31), done.
Delta compression using up to 8 threads
Compressing objects: 100% (23/23), done.
Writing objects: 100% (23/23), 5.60 KiB | 212.00 KiB/s, done.
Total 23 (delta 14), reused 0 (delta 0)
[{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 12803
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=12803, si_uid=1000, si_status=0, si_utime=2, si_stime=6} ---
read(3,
------------------
That last read from handle 3 (which is closed) lasts forever until you ctrl-c.
The abbreviated strace output, simply halting at the comma, is very odd.
Note the behaviour is the same with the file: protocol prefix and without.
j.
