shithub: riscv

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ref: b96573b481440455ea92c67a0bc629b88901b319
parent: c309f466eff33a331f9a8d8c8b18cfe613c1d3f4
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Thu Mar 28 17:52:38 EDT 2024

kernel: zero up->ureg on sysexec() and pexit()

The up->ureg pointer points to the last delivered
note in the user-space stack.

On exec(), all the notes are cleared and the
ureg pointer should be zeroed as well as it
points into the previous programs stack.

Note, this can only happen if someone does
exec() from a note handler.

When we pexit(), also zero the up->ureg and up->dbgreg
as we are about to release the memory segments
and nobody should debugging user-space anymore.

--- a/sys/src/9/port/proc.c
+++ b/sys/src/9/port/proc.c
@@ -1348,6 +1348,8 @@
 	freenote(up->lastnote);
 	up->lastnote = nil;
 	up->notified = 0;
+	up->ureg = nil;
+	up->dbgreg = nil;
 
 	/* release debuggers */
 	if(up->pdbg != nil) {
--- a/sys/src/9/port/sysproc.c
+++ b/sys/src/9/port/sysproc.c
@@ -607,6 +607,7 @@
 	up->lastnote = nil;
 	up->notify = nil;
 	up->notified = 0;
+	up->ureg = nil;
 	up->privatemem = 0;
 	up->noswap = 0;
 	up->pcycles = -up->kentry;