"Invalid argument" on creating file in 9p filesystem (Linux)

[SuperMaxusa]

Linux (from 6.6.x) can't create file on mounted host9p by mount -t 9p host9p /mnt, returning an error Invalid argument (-1 EINVAL), also this error showing on ls.

strace (ls)

execve("/bin/ls", ["ls", "/mnt"], 0xbfdeff4c /* 12 vars */) = 0
set_thread_area({entry_number=-1, base_addr=0xb7f7bc64, limit=0x0fffff, seg_32bit=1, contents=0, read_exec_only=0, limit_in_pages=1, seg_not_present=0, useable=1}) = 0 (entry_number=6)
set_tid_address(0xb7f7bcfc)             = 1930
brk(NULL)                               = 0x13d4000
brk(0x13d6000)                          = 0x13d6000
mmap2(0x13d4000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x13d4000
mprotect(0xb7f79000, 4096, PROT_READ)   = 0
mprotect(0x551000, 8192, PROT_READ)     = 0
getuid32()                              = 0
ioctl(0, TIOCGWINSZ, {ws_row=48, ws_col=128, ws_xpixel=0, ws_ypixel=400}) = 0
ioctl(1, TIOCGWINSZ, {ws_row=48, ws_col=128, ws_xpixel=0, ws_ypixel=400}) = 0
ioctl(1, TIOCGWINSZ, {ws_row=48, ws_col=128, ws_xpixel=0, ws_ypixel=400}) = 0
statx(AT_FDCWD, "/mnt", AT_STATX_SYNC_AS_STAT, STATX_BASIC_STATS, {stx_mask=STATX_BASIC_STATS|STATX_MNT_ID, stx_attributes=STATX_ATTR_MOUNT_ROOT, stx_mode=S_IFDIR|0777, stx_size=0, ...}) = 0
open("/mnt", O_RDONLY|O_LARGEFILE|O_CLOEXEC|O_DIRECTORY) = 3
fcntl64(3, F_SETFD, FD_CLOEXEC)         = 0
mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7ed1000
getdents64(3, 0xb7ed1038 /* 4 entries */, 2048) = 120
statx(AT_FDCWD, "/mnt/testfile", AT_STATX_SYNC_AS_STAT|AT_SYMLINK_NOFOLLOW, STATX_BASIC_STATS, 0xbf8d56c0) = -1 EINVAL (Invalid argument)
write(2, "ls: /mnt/testfile: Invalid argum"..., 36) = 36
statx(AT_FDCWD, "/mnt/file_from_host.txt", AT_STATX_SYNC_AS_STAT|AT_SYMLINK_NOFOLLOW, STATX_BASIC_STATS, {stx_mask=STATX_BASIC_STATS|STATX_MNT_ID, stx_attributes=0, stx_mode=S_IFREG|0666, stx_size=0, ...}) = 0
getdents64(3, 0xb7ed1038 /* 0 entries */, 2048) = 0
close(3)                                = 0
munmap(0xb7ed1000, 8192)                = 0
ioctl(1, TIOCGWINSZ, {ws_row=48, ws_col=128, ws_xpixel=0, ws_ypixel=400}) = 0
writev(1, [{iov_base="\33[0;0mfile_from_host.txt\33[m", iov_len=27}, {iov_base="\n", iov_len=1}], 2) = 28
exit_group(1)                           = ?
+++ exited with 1 +++

strace (touch)

execve("/bin/touch", ["touch", "/mnt/testfile"], 0xbf92b1bc /* 12 vars */) = 0
set_thread_area({entry_number=-1, base_addr=0xb7f7cc64, limit=0x0fffff, seg_32bit=1, contents=0, read_exec_only=0, limit_in_pages=1, seg_not_present=0, useable=1}) = 0 (entry_number=6)
set_tid_address(0xb7f7ccfc)             = 1923
brk(NULL)                               = 0x1723000
brk(0x1725000)                          = 0x1725000
mmap2(0x1723000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x1723000
mprotect(0xb7f7a000, 4096, PROT_READ)   = 0
mprotect(0x546000, 8192, PROT_READ)     = 0
getuid32()                              = 0
utimensat(AT_FDCWD, "/mnt/testfile", NULL, 0) = -1 ENOENT (No such file or directory)
open("/mnt/testfile", O_RDWR|O_CREAT|O_LARGEFILE, 0666) = -1 EINVAL (Invalid argument)
write(2, "touch: /mnt/testfile: Invalid ar"..., 39) = 39
exit_group(1)                           = ?
+++ exited with 1 +++

Note for Alpine Linux: the bug is only on v3.19 (from 3.19.0 RC2 and above, this does not apply to previous versions):

Alpine's version	Kernel version	Have a bug?
3.18.6	6.1.75	no
3.19.0 RC1	6.1.62	no
3.19.0 RC2	6.6.3	yes
3.19.1	6.6.14	yes

[farhan-ct]

I have a similar issue when trying to open node console on alpine. It gives me an error saying 'x' invalid argument found or something. Will add more details later. Please ignore if this is irrelevant.

[SuperMaxusa]

trying to open node console on alpine.

did you tried run node with script without repl (or node -e "console.log('hello')") or this is also not working?

[farhan-ct]

did you tried run node with script without repl (or node -e "console.log('hello')") or this is also not working?

Am able to run node scripts without issues. issue was for node console only. Will try node -e "console.log('hello')" too and update here.

[farhan-ct]

@SuperMaxusa regarding the node issue I mentioned earlier, nothing to worry about, it's #875 . I noticed it earlier but just confirming the same here.

[SuperMaxusa]

This also reproduces in Void Linux 2024-03-14, so it's problem of Linux kernel 6.6.x (or earlier), not just Alpine

[farhan-ct]

Issue in debian too :( with 9pfs

[farhan-ct]

How do we fix this? I can try but will need some guidance. Issue is reproducable in the provided debian docker build in this repo too.

[SuperMaxusa]

I have some thoughts about this commit in linux repo: torvalds/linux@3866584, but I'm not entirely sure. Because of that reason, probably, open() and statx() returns EINVAL about incorrect flags.

Issue is reproducable in the provided debian docker build in this repo too.

Can you provide which kernel version is installed in rootfs? Seems a Dockerfile created on Debian Buster, which linux-image-686 has latest version as 4.19, or it's automatically updates?

[farhan-ct]

Seems a Dockerfile created on Debian Buster, which linux-image-686 has latest version as 4.19

Its auto-updated so the current version in it is 6.6.15-686

However, I downloaded and installed linux-image 5.10.0 (5.10.0-0.deb10.28-686) kernel but trying to figure out where I can change the default kernel version when booting :(

I am trying to see if 9p mounted with 5.10.0 linux-image would resolve the problem if its due to compatibility like you mentioned.

[farhan-ct]

My above reply is wrong, I changed it to trixie earlier. Buster doesn't have the 9p issue, working perfectly fine.

[copy]

Will be fixed in 2ca82a5.

[SuperMaxusa]

Thanks, works for me on Linux 6.6 without any problems.

@farhan-ct can you try build v86 from wip branch and test on newer Alpine (3.18.6+) or Debian (trixie+) versions?

[farhan-ct]

Yes this issue is fixed and works in debian trixie+ too.

We can close this issue now (or maybe after new release)