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| author | Rich Felker <dalias@aerifal.cx> | 2020-09-28 18:38:27 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2020-09-28 18:56:20 -0400 |
| commit | 34904d830a9fd1f6fc47218f38c111698303d2fe (patch) | |
| tree | c43e8b5659386f5a3ed4f5e749d389f2fb91027b /src/process | |
| parent | a5aff1972c9e3981566414b09a28e331ccd2be5d (diff) | |
| download | musl-34904d830a9fd1f6fc47218f38c111698303d2fe.tar.gz | |
fix fork of processes with active async io contexts
previously, if a file descriptor had aio operations pending in the
parent before fork, attempting to close it in the child would attempt
to cancel a thread belonging to the parent. this could deadlock, fail,
or crash the whole process of the cancellation signal handler was not
yet installed in the parent. in addition, further use of aio from the
child could malfunction or deadlock.
POSIX specifies that async io operations are not inherited by the
child on fork, so clear the entire aio fd map in the child, and take
the aio map lock (with signals blocked) across the fork so that the
lock is kept in a consistent state.
Diffstat (limited to 'src/process')
| -rw-r--r-- | src/process/fork.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/process/fork.c b/src/process/fork.c index 7e984ff8..dbaa9402 100644 --- a/src/process/fork.c +++ b/src/process/fork.c @@ -10,6 +10,7 @@ static void dummy(int x) } weak_alias(dummy, __fork_handler); +weak_alias(dummy, __aio_atfork); pid_t fork(void) { @@ -17,6 +18,7 @@ pid_t fork(void) sigset_t set; __fork_handler(-1); __block_all_sigs(&set); + __aio_atfork(-1); #ifdef SYS_fork ret = __syscall(SYS_fork); #else @@ -32,6 +34,7 @@ pid_t fork(void) libc.threads_minus_1 = 0; if (libc.need_locks) libc.need_locks = -1; } + __aio_atfork(!ret); __restore_sigs(&set); __fork_handler(!ret); return __syscall_ret(ret); |