From: Florin Postolache <florin.postolache.of@gmail.com>
Date: Thu, 11 May 2023 10:07:48 +0000 (+0300)
Subject: lib/posix-process: Reserve PID/TID 0 for kernel
X-Git-Tag: RELEASE-0.13.0~19
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=d4100c9dc4dfffdebd48ce8788d04ca3fa75d066;p=unikraft%2Funikraft.git

lib/posix-process: Reserve PID/TID 0 for kernel

This commit marks the TID/PID as unavailable to mimic the behaviour of
other kernels. This change also make pthread_rwlocks from glibc work in
binary compatibility mode.

Signed-off-by: Florin Postolache <florin.postolache.of@gmail.com>
Reviewed-by: Simon Kuenzer <simon@unikraft.io>
Reviewed-by: Andra Paraschiv <andra@unikraft.org>
Approved-by: Simon Kuenzer <simon@unikraft.io>
Tested-by: Unikraft CI <monkey@unikraft.io>
GitHub-Closes: #885
---

diff --git a/lib/posix-process/process.c b/lib/posix-process/process.c
index ddea9631e..02ad05fbb 100644
--- a/lib/posix-process/process.c
+++ b/lib/posix-process/process.c
@@ -83,9 +83,11 @@ struct posix_thread {
 
 /**
  * System global lists
+ * NOTE: We pre-allocate PID/TID 0 which is reserved by the kernel.
+ *       An application should never get PID/TID 0 assigned.
  */
 static struct posix_thread *tid_thread[TIDMAP_SIZE];
-static unsigned long tid_map[UK_BITS_TO_LONGS(TIDMAP_SIZE)];
+static unsigned long tid_map[UK_BITS_TO_LONGS(TIDMAP_SIZE)] = { [0] = 0x01UL };
 
 /**
  * Thread-local posix_thread reference