Re: [PATCH] man/man2/clone.2: Use munmap() to free child stack
From: Alejandro Colomar <alx@kernel.org>
Date: 2025-02-02 16:56:14
Hi Chen, On Tue, Jan 21, 2025 at 11:13:51AM +0800, Chen Linxuan wrote:
quoted hunk ↗ jump to hunk
While reading the help manual for clone.2, I notice that the parent process in the example code does not release the stack of the child process. This is not a problem for the example program, but it is somewhat misleading. Signed-off-by: Chen Linxuan <redacted> --- man/man2/clone.2 | 2 ++ 1 file changed, 2 insertions(+)diff --git a/man/man2/clone.2 b/man/man2/clone.2 index 3ffe8e7b8..5e6b2ef1f 100644 --- a/man/man2/clone.2 +++ b/man/man2/clone.2@@ -1910,6 +1910,8 @@ main(int argc, char *argv[]) child commences execution in childFunc(). */ \& pid = clone(childFunc, stackTop, CLONE_NEWUTS | SIGCHLD, argv[1]); + if (munmap(stack, STACK_SIZE)) + err(EXIT_FAILURE, "munmap"); if (pid == \-1)
Would you mind clarifying why this munmap(2) call goes before the error handling of clone(2)? I'm not very familiar with clone(2). Have a lovely day! Alex
err(EXIT_FAILURE, "clone");
printf("clone() returned %jd\[rs]n", (intmax_t) pid);
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2.43.0-- <https://www.alejandro-colomar.es/>
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