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From: "Alex Xu (Hello71)" <>
Subject: Re: [musl] BUG: Calling readdir/dirfd after vfork will cause deadlock.
Date: Sat, 25 Jun 2022 08:56:46 -0400	[thread overview]
Message-ID: <1656161421.nztip0vma0.none@localhost> (raw)
In-Reply-To: <>

Excerpts from Nick Peng's message of June 24, 2022 11:40 pm:
> Description:  After vfork, calling functions such as readdir/dirfd may
> cause deadlock. GNU C is OK.

This is not a bug. TFM:

   Standard description
       (From  POSIX.1)  The vfork() function has the same effect as 
       fork(2), except that the behavior is undefined if the process 
       created by vfork() either modifies any data other than a variable 
       of type pid_t used to store the return value from vfork(), or 
       returns from the function in which vfork() was called, or calls 
       any other function before successfully calling _exit(2) or one of 
       the exec(3) family of functions.

It may happen to appear to work in some cases on some libcs, or kernels, 
or architectures, or it may deadlock, corrupt data, or cause demons to 
fly out your nose. Do not use vfork in this manner. Avoid using fork in 
this manner either; that may work in musl 1.2.2+, and appear to work in 
glibc (but sometimes randomly corrupt data), but is not portable to 
other libcs.


  parent reply	other threads:[~2022-06-25 12:57 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-25  3:40 Nick Peng
2022-06-25 12:51 ` Szabolcs Nagy
2022-06-27  4:05   ` Nick Peng
2022-06-27 10:38     ` Laurent Bercot
2022-06-27 14:21     ` Rich Felker
2022-06-27 14:29     ` Markus Wichmann
2022-06-27  7:42   ` Florian Weimer
2022-06-27  8:37     ` Szabolcs Nagy
2022-06-27  9:23       ` Florian Weimer
2022-06-27 17:33         ` Szabolcs Nagy
2022-06-25 12:56 ` Alex Xu (Hello71) [this message]
2022-06-27  7:44   ` Florian Weimer
2022-06-27 12:28     ` Alex Xu (Hello71)

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