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Diffstat (limited to 'gitlab/issues/target_missing/host_missing/accel_missing/2825.toml')
| -rw-r--r-- | gitlab/issues/target_missing/host_missing/accel_missing/2825.toml | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/gitlab/issues/target_missing/host_missing/accel_missing/2825.toml b/gitlab/issues/target_missing/host_missing/accel_missing/2825.toml new file mode 100644 index 00000000..787cc70b --- /dev/null +++ b/gitlab/issues/target_missing/host_missing/accel_missing/2825.toml @@ -0,0 +1,45 @@ +id = 2825 +title = "execveat with file descriptor and empty filename returns ENOENT when cross architectures" +state = "opened" +created_at = "2025-02-21T13:01:36.698Z" +closed_at = "n/a" +labels = [] +url = "https://gitlab.com/qemu-project/qemu/-/issues/2825" +host-os = "Debian 12" +host-arch = "x86" +qemu-version = "9.2.0" +guest-os = "n/a" +guest-arch = "n/a" +description = """On my x86_64 debian host (with binfmt_misc configured), when calling execveat with a fd , and empty pathname "", and flag AT_EMPTY_PATH. Then only x86_64 and x86 can be called normally, while programs of other architectures (arm64, arm, riscv64, etc.) will return ENOENT errors. + +I first encountered this problem when trying to run lxc-attach with qemu-aarch64. Its reference is [lxc/stable-6.0/src/include/fexecve.c#L30](https://github.com/lxc/lxc/blob/stable-6.0/src/include/fexecve.c#L30), which is the implementation of the fexecve function. So I wrote a simple test and compiled it with `x86_64/aarch64-linux-gnu-gcc -static test.c -o test`. execveat works fine when running natively or using qemu-x86_64/qemu-i386. When running versions for other architectures, using AT_EMPTY_PATH will result in ENOENT (No such file or directory); use /proc/self/fd/%d as the pathname and execve, it will work fine (like the rest part of the fexecve function). If binfmt_misc is turned off and run forign architectures ver, both calls will result in ENOEXEC (Exec format error).""" +reproduce = """1. Install qemu-user and binfmt_misc. Install gcc-aarch64-linux-gnu/gcc-riscv64-linux-gnu etc. +2. Compile test.c with host gcc, then compile forign architectures ver with gcc-aarch64-linux-gnu/gcc-riscv64-linux-gnu etc. like `gcc -static test.c -o test` and `aarch64-linux-gnu-gcc -static test.c -o test-aarch64` +3. Run different versions of test +4. To disable/enable binfmt, you can `echo 0 > /proc/sys/fs/binfmt_misc/qemu-aarch64` or `echo 1 > /proc/sys/fs/binfmt_misc/qemu-aarch64` +5. Sample outputs + +``` +rrex@debian:~/Downloads$ ./test +****Running to prepare execve +fd=3 +File size: 772296 bytes + +execveat with AT_EMPTY_PATH: +**Running in execve + +execveat with fd path: /proc/self/fd/3 +**Running in execve + +rrex@debian:~/Downloads$ qemu-aarch64 ./test-aarch64 +****Running to prepare execve +fd=3 +File size: 706104 bytes + +execveat with AT_EMPTY_PATH: +!!execveat a fd failed with errno: No such file or directory + +execveat with fd path: /proc/self/fd/3 +**Running in execve +```""" +additional = """#""" |