motiejus/zig

commit 6d23850108b5d3278f5b1cad395ff8da4fdfebeb (tree)
parent f988cea825c4b21d0864e7125287b12566079c39
Author: Alex Rønne Petersen <alex@alexrp.com>
Date:   Mon, 12 Aug 2024 04:10:27 +0200

std.Thread: Explain apparently pointless mips instruction in freeAndExit().

https://git.musl-libc.org/cgit/musl/commit/?id=ce3688eca920aa77549323f84e21f33522397115

Diffstat:
M
lib/std/Thread.zig
 | 
4
++++

1 file changed, 4 insertions(+), 0 deletions(-)
diff --git a/lib/std/Thread.zig b/lib/std/Thread.zig
@@ -1130,6 +1130,10 @@ const LinuxThreadImpl = struct {
                       [len] "r" (self.mapped.len),
                     : "memory"
                 ),
+                // We set `sp` to the address of the current function as a workaround for a Linux
+                // kernel bug that caused syscalls to return EFAULT if the stack pointer is invalid.
+                // The bug was introduced in 46e12c07b3b9603c60fc1d421ff18618241cb081 and fixed in
+                // 7928eb0370d1133d0d8cd2f5ddfca19c309079d5.
                 .mips, .mipsel => asm volatile (
                     \\  move $sp, $25
                     \\  li $2, 4091 # SYS_munmap