# IOError: could not spawn \<...\>: argument list too long

**URL:** <https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728>\
**Category:** New to Julia\
**Created:** [July 26, 2020, 11:02pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728 "2020-07-26T23:02:48Z")\
**Posts on this page:** 20\
**Page:** 1

<div class="post-metadata">

**Author:** ![aplavin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aplavin/32/222056_2.png) [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Post date:** [July 26, 2020, 11:02pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/1 "2020-07-26T23:02:48Z")

</div>

I have a script that looks like this:

```julia
Threads.@threads for x in ...
    ...
    out = Pipe()
    err = Pipe()
    cmd = Cmd(`<executable_file>`, ignorestatus=true, dir=tmp_dir)
    process = run(pipeline(cmd, stdin=joinpath(tmp_dir, "commands"), stdout=out, stderr=err), wait=true)
    ...
end

```

Generally it works fine, but from time to time (after several hours) I get this exception:

```julia
ERROR: LoadError: TaskFailedException:
IOError: could not spawn setenv(`/home/aplavin/.../<executable_file>`; dir="/tmp/<temp_dir_name>"): argument list too long (E2BIG)
 [1] _spawn_primitive(::String, ::Cmd, ::Array{Any,1}) at ./process.jl:99
 [2] #550 at ./process.jl:112 [inlined]
 [3] setup_stdios(::Base.var"#550#551"{Cmd}, ::Array{Any,1}) at ./process.jl:196
 [4] _spawn at ./process.jl:111 [inlined]
 [5] _spawn(::Base.CmdRedirect, ::Array{Any,1}) at ./process.jl:139 (repeats 3 times)
 [6] run(::Base.CmdRedirect; wait::Bool) at ./process.jl:439
 [7] <line with run(pipeline(...)) from the code above>

```

Note that there are no command-line arguments in this `run` call, and the executable name is short. Moreover, when I run my script again, it skips already processed items in the for loop (by design), and successfully completes the iteration for the same `x` it failed before. Then after some time I get the same exception, and have to restart the script again.

Unfortunately, I could not make an MWE for this, and not even sure whether it is related to threads - the same loop without threads runs for longer without errors, but maybe it is just a matter of waiting more.

Any idea why this may happen, and how to fix/debug this error?

---

<div class="post-metadata">

**Author:** ![aplavin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aplavin/32/222056_2.png) [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Post date:** [November 5, 2020, 1:01pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/2 "2020-11-05T13:01:23Z")

</div>

Turns out I can reliably reproduce a state when Julia cannot execute any external command, i.e. even `run(`ls`)` raises the aforementioned error `IOError: could not spawn `ls`: argument list too long (E2BIG)`. The reproduction basically consists of running the script described in the first post for some time.  
I still cannot provide an MWE, but will gladly try to debug the issue is anyone provides some pointers on what to try when `run(`ls`)` fails.

This happens for latest Julia (1.5.2) on linux.

---

<div class="post-metadata">

**Author:** ![jpsamaroo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jpsamaroo/32/46804_2.png) [@jpsamaroo](https://discourse.julialang.org/u/jpsamaroo)\
**Post date:** [November 5, 2020, 1:04pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/3 "2020-11-05T13:04:04Z")

</div>

This will probably take a while and use a good bit of disk space, but you could run this under `strace`, wait for it to fail and terminate, and then check the strace log for the failing syscall. `strace` will show you the exact command and arguments used.

---

<div class="post-metadata">

**Author:** ![aplavin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aplavin/32/222056_2.png) [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Post date:** [November 5, 2020, 1:18pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/4 "2020-11-05T13:18:28Z")

</div>

For now I tried attaching `strace` to the Julia process when it’s in the “ls-failing” state. So I attach strace, execute `run(`ls`)`, but don’t see anything like “spawn” in the log. What exactly to look for?

---

<div class="post-metadata">

**Author:** ![aplavin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aplavin/32/222056_2.png) [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Post date:** [November 5, 2020, 1:23pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/5 "2020-11-05T13:23:07Z")

</div>

I found `vfork` in the strace log. The seemingly-relevant part around:

```julia
write(16, "\1\0\0\0\0\0\0\0\207@\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 44) = 44
epoll_ctl(3, EPOLL_CTL_MOD, 16, {EPOLLIN, {u32=16, u64=16}}) = 0
epoll_pwait(3, [], 1024, 0, NULL, 8) = 0
epoll_pwait(3, [], 1024, 0, NULL, 8) = 0
epoll_pwait(3, [{EPOLLIN, {u32=16, u64=16}}], 1024, -1, NULL, 8) = 1
read(16, "\1\0\0\0\0\0\0\0\210@\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 67369) = 1239
epoll_pwait(3, [], 1024, 0, NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [INT QUIT ABRT USR1 TERM], 8) = 0
rt_sigprocmask(SIG_SETMASK, ~[RTMIN RT_1], [INT QUIT ABRT USR1 TERM], 8) = 0
vfork() = 16526
rt_sigprocmask(SIG_SETMASK, [INT QUIT ABRT USR1 TERM], NULL, 8) = 0
rt_sigprocmask(SIG_SETMASK, ~[RTMIN RT_1], [INT QUIT ABRT USR1 TERM], 8) = 0
rt_sigprocmask(SIG_SETMASK, [INT QUIT ABRT USR1 TERM], NULL, 8) = 0
mincore(0x7f0fb9c84000, 4096, [1]) = 0
read(17, "\7", 1) = 1
write(18, "2", 1) = 1
mincore(0x7f0fb9c85000, 4096, [1]) = 0
read(17, "2", 1) = 1
write(18, "\0", 1) = 1

```

This corresponds to the failing run(`ls`). As I’m not familiar with stracing, can you please help me make some sense out of it?

---

<div class="post-metadata">

**Author:** ![jpsamaroo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jpsamaroo/32/46804_2.png) [@jpsamaroo](https://discourse.julialang.org/u/jpsamaroo)\
**Post date:** [November 5, 2020, 1:41pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/6 "2020-11-05T13:41:22Z")

</div>

Ok good, so what you’ll need to do is to run `strace` with either the `-f` or `-ff` flags to see what the forked process is doing.

---

<div class="post-metadata">

**Author:** ![aplavin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aplavin/32/222056_2.png) [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Post date:** [November 5, 2020, 2:24pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/7 "2020-11-05T14:24:31Z")

</div>

That’s the strace log of a forked process:

```julia
fcntl(0, F_GETFD) = 0
fcntl(0, F_GETFL) = 0 (flags O_RDONLY)
fcntl(1, F_GETFD) = 0
fcntl(1, F_GETFL) = 0x1 (flags O_WRONLY)
fcntl(2, F_GETFD) = 0
fcntl(2, F_GETFL) = 0x1 (flags O_WRONLY)
rt_sigaction(SIGHUP, {sa_handler=SIG_DFL, sa_mask=[HUP], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGINT, {sa_handler=SIG_DFL, sa_mask=[INT], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=0x7fc7d6b84ff0, sa_mask=[], sa_flags=SA_RESTORER, sa_restorer=0x7fc7d6a4a140}, 8) = 0
rt_sigaction(SIGQUIT, {sa_handler=SIG_DFL, sa_mask=[QUIT], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGILL, {sa_handler=SIG_DFL, sa_mask=[ILL], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=0x7fc7d6b851d0, sa_mask=[], sa_flags=SA_RESTORER|SA_SIGINFO, sa_restorer=0x7fc7d6a4a140}, 8) = 0
rt_sigaction(SIGTRAP, {sa_handler=SIG_DFL, sa_mask=[TRAP], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_IGN, sa_mask=[TRAP], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, 8) = 0
rt_sigaction(SIGABRT, {sa_handler=SIG_DFL, sa_mask=[ABRT], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=0x7fc7d6b851d0, sa_mask=[], sa_flags=SA_RESTORER|SA_SIGINFO, sa_restorer=0x7fc7d6a4a140}, 8) = 0
rt_sigaction(SIGBUS, {sa_handler=SIG_DFL, sa_mask=[BUS], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=0x7fc7d6b857f0, sa_mask=[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_SIGINFO, sa_restorer=0x7fc7d6a4a140}, 8) = 0
rt_sigaction(SIGFPE, {sa_handler=SIG_DFL, sa_mask=[FPE], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=0x7fc7d6b850f0, sa_mask=[], sa_flags=SA_RESTORER|SA_SIGINFO, sa_restorer=0x7fc7d6a4a140}, 8) = 0
rt_sigaction(SIGUSR1, {sa_handler=SIG_DFL, sa_mask=[USR1], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=0x7fc7d6b851d0, sa_mask=[], sa_flags=SA_RESTORER|SA_RESTART|SA_SIGINFO, sa_restorer=0x7fc7d6a4a140}, 8) = 0
rt_sigaction(SIGSEGV, {sa_handler=SIG_DFL, sa_mask=[SEGV], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=0x7fc7d6b857f0, sa_mask=[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_SIGINFO, sa_restorer=0x7fc7d6a4a140}, 8) = 0
rt_sigaction(SIGUSR2, {sa_handler=SIG_DFL, sa_mask=[USR2], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=0x7fc7d6b85460, sa_mask=[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x7fc7d6a4a140}, 8) = 0
rt_sigaction(SIGPIPE, {sa_handler=SIG_DFL, sa_mask=[PIPE], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_IGN, sa_mask=[PIPE], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, 8) = 0
rt_sigaction(SIGALRM, {sa_handler=SIG_DFL, sa_mask=[ALRM], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGTERM, {sa_handler=SIG_DFL, sa_mask=[TERM], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGSTKFLT, {sa_handler=SIG_DFL, sa_mask=[STKFLT], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGCHLD, {sa_handler=SIG_DFL, sa_mask=[CHLD], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=0x7fc7d6c4d222, sa_mask=~[KILL STOP RTMIN RT_1], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d6a4a140}, 8) = 0
rt_sigaction(SIGCONT, {sa_handler=SIG_DFL, sa_mask=[CONT], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGTSTP, {sa_handler=SIG_DFL, sa_mask=[TSTP], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGTTIN, {sa_handler=SIG_DFL, sa_mask=[TTIN], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGTTOU, {sa_handler=SIG_DFL, sa_mask=[TTOU], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGURG, {sa_handler=SIG_DFL, sa_mask=[URG], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGXCPU, {sa_handler=SIG_DFL, sa_mask=[XCPU], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGXFSZ, {sa_handler=SIG_DFL, sa_mask=[XFSZ], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGVTALRM, {sa_handler=SIG_DFL, sa_mask=[VTALRM], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGPROF, {sa_handler=SIG_DFL, sa_mask=[PROF], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGWINCH, {sa_handler=SIG_DFL, sa_mask=[WINCH], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGIO, {sa_handler=SIG_DFL, sa_mask=[IO], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGPWR, {sa_handler=SIG_DFL, sa_mask=[PWR], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGSYS, {sa_handler=SIG_DFL, sa_mask=[SYS], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7fc7d68ace30}, {sa_handler=0x7fc7d6b851d0, sa_mask=[], sa_flags=SA_RESTORER|SA_SIGINFO, sa_restorer=0x7fc7d6a4a140}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
execve("/home/aplavin/.julia/artifacts/595a9c11691838de1f6ed43bfe902f7885cb366a/bin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)
execve("/home/aplavin/.julia/artifacts/4b3f429bc2c468e7cb44b1670a262b13be4528f6/bin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)

<... same lines repeating many times ...>

execve("/home/aplavin/.julia/artifacts/4b3f429bc2c468e7cb44b1670a262b13be4528f6/bin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)
execve("/home/aplavin/.julia/artifacts/595a9c11691838de1f6ed43bfe902f7885cb366a/bin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)
execve("/home/aplavin/.julia/artifacts/4b3f429bc2c468e7cb44b1670a262b13be4528f6/bin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)
execve("/home/aplavin/.julia/artifacts/595a9c11691838de1f6ed43bfe902f7885cb366a/bin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)
execve("/home/aplavin/.julia/artifacts/4b3f429bc2c468e7cb44b1670a262b13be4528f6/bin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)
execve("/home/aplavin/anaconda3/bin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)
execve("/usr/local/sbin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)
execve("/usr/local/bin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)
execve("/usr/sbin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)
execve("/usr/bin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)
execve("/sbin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 ENOENT (No such file or directory)
execve("/bin/ls", ["ls"], 0x23ab620 /* 40 vars */) = -1 E2BIG (Argument list too long)
exit_group(127) = ?
+++ exited with 127 +++

```

---

<div class="post-metadata">

**Author:** ![jpsamaroo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jpsamaroo/32/46804_2.png) [@jpsamaroo](https://discourse.julialang.org/u/jpsamaroo)\
**Post date:** [November 5, 2020, 3:01pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/8 "2020-11-05T15:01:41Z")

</div>

Are you doing any manipulations of the env. vars during runtime? I suspect that you might have too many env. vars set (and their combined length is too long) leading to `E2BIG`.

---

<div class="post-metadata">

**Author:** ![aplavin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aplavin/32/222056_2.png) [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Post date:** [November 5, 2020, 3:18pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/9 "2020-11-05T15:18:19Z")

</div>

Don’t think there are any env modifications at all. I never even access `ENV` in the code.

---

<div class="post-metadata">

**Author:** ![aplavin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aplavin/32/222056_2.png) [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Post date:** [November 5, 2020, 3:23pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/10 "2020-11-05T15:23:39Z")

</div>

Now I checked `ENV`, and turns out that `ENV["PATH"]` is very long: it contains many repetitions of two directories, the ones in the strace log above. One of them points to a julia artifact used in the script, and the other points to a completely unrelated artifact. But I don’t append anything to `PATH` myself, so where could these repetitions come from?

---

<div class="post-metadata">

**Author:** ![jpsamaroo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jpsamaroo/32/46804_2.png) [@jpsamaroo](https://discourse.julialang.org/u/jpsamaroo)\
**Post date:** [November 5, 2020, 4:58pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/11 "2020-11-05T16:58:41Z")

</div>

They’re likely automatically set by Julia’s artifact system to ensure binaries and libraries provided by artifacts are accessible to external commands. About how long are these paths (in terms of bytes)?

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<div class="post-metadata">

**Author:** ![aplavin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aplavin/32/222056_2.png) [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Post date:** [November 5, 2020, 5:40pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/12 "2020-11-05T17:40:22Z")

</div>

Each (of the two) path is short, e.g. “/home/aplavin/.julia/artifacts/4b3f429bc2c468e7cb44b1670a262b13be4528f6/bin/”. However, the same two paths are repeated many many times in `ENV["PATH"]`, so `length(ENV["PATH"]) > 17000`.

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<div class="post-metadata">

**Author:** ![jpsamaroo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jpsamaroo/32/46804_2.png) [@jpsamaroo](https://discourse.julialang.org/u/jpsamaroo)\
**Post date:** [November 5, 2020, 6:03pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/13 "2020-11-05T18:03:18Z")

</div>

Ok that’s definitely the issue then. I’m not familiar with how this system works, but maybe @giordano has some ideas?

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<div class="post-metadata">

**Author:** ![giordano](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/giordano/32/2166_2.png) [@giordano](https://discourse.julialang.org/u/giordano)\
**Post date:** [November 5, 2020, 6:16pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/14 "2020-11-05T18:16:58Z")

</div>

Not sure what we are talking about. Unless I missed something, you aren’t running an `ExecutableProduct` in a JLL package? If so, I have no idea what’s setting your `PATH`.

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<div class="post-metadata">

**Author:** ![aplavin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aplavin/32/222056_2.png) [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Post date:** [November 5, 2020, 6:51pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/15 "2020-11-05T18:51:02Z")

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I do run an executable from a jll package many times in my script (see 1st post for description), and this leads to a long `ENV["PATH"]`. I would guess that running a jll package somehow appends to `PATH` and doesn’t always revert the changes in a multithreaded/async scenario.

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**Author:** ![giordano](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/giordano/32/2166_2.png) [@giordano](https://discourse.julialang.org/u/giordano)\
**Post date:** [November 5, 2020, 6:59pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/16 "2020-11-05T18:59:03Z")

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> [@aplavin](#):
>
> I do run an executable from a jll package many times in my script (see 1st post for description)

No mention to JLLs as far as I can see 🙂

Can you please provide a MWE? Hard to understand what’s happening without having a simple code to look at

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**Author:** ![aplavin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aplavin/32/222056_2.png) [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Post date:** [November 5, 2020, 7:05pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/17 "2020-11-05T19:05:52Z")

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Indeed, I didn’t think that jlls were relevant when writing the 1st post. Anyway, for now I solved the issue by specifying `adjust_PATH=false` and `adjust_LIBPATH=false` when running a jll executable. This way no changes are done to ENV and `ENV["PATH"]` doesn’t grow.

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<div class="post-metadata">

**Author:** ![aplavin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aplavin/32/222056_2.png) [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Post date:** [November 5, 2020, 7:07pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/18 "2020-11-05T19:07:43Z")

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Thanks for helping to debug this! I wouldn’t ever guess that the error has something to do with ENV values, and that those values may grow unexpectedly.

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**Author:** ![giordano](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/giordano/32/2166_2.png) [@giordano](https://discourse.julialang.org/u/giordano)\
**Post date:** [November 5, 2020, 7:13pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/19 "2020-11-05T19:13:59Z")

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I think that in Julia v1.6 the thread-safe `addenv` function is used, while in previous versions `withenv` is used, which is known to be thread-unsafe: [https://github.com/JuliaLang/julia/issues/34726](https://github.com/JuliaLang/julia/issues/34726)

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<div class="post-metadata">

**Author:** ![aplavin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/aplavin/32/222056_2.png) [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Post date:** [November 5, 2020, 7:18pm UTC](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728/20 "2020-11-05T19:18:21Z")

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Oh, interesting - this looks like the underlying cause. So JLL packages will work without this issue in the next julia version? Or some manual modifications will be needed?

[Next page](https://discourse.julialang.org/t/ioerror-could-not-spawn-argument-list-too-long/43728.md?page=2)