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daemon: Ensure the child stack is aligned on a 16-byte boundary. 

* nix/libstore/build.cc (DerivationGoal::startBuilder): When calling 'clone',
ensure that the stack is aligned on a 16-byte boundary.
This commit is contained in:
Mark H Weaver 2017-08-07 16:41:03 -04:00
parent 73a203450d
commit a1aa5dabaa
No known key found for this signature in database
GPG Key ID: 7CEF29847562C516
1 changed files with 6 additions and 5 deletions
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11
nix/libstore/build.cc
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@ -26,6 +26,7 @@
#include <errno.h> #include <errno.h>
#include <stdio.h> #include <stdio.h>
#include <cstring> #include <cstring>
#include <stdint.h>
#include <pwd.h> #include <pwd.h>
#include <grp.h> #include <grp.h>
@ -2008,11 +2009,11 @@ void DerivationGoal::startBuilder()
char stack[32 * 1024]; char stack[32 * 1024];
int flags = CLONE_NEWPID | CLONE_NEWNS | CLONE_NEWIPC | CLONE_NEWUTS | SIGCHLD; int flags = CLONE_NEWPID | CLONE_NEWNS | CLONE_NEWIPC | CLONE_NEWUTS | SIGCHLD;
if (!fixedOutput) flags |= CLONE_NEWNET; if (!fixedOutput) flags |= CLONE_NEWNET;
#ifdef __aarch64__ /* Ensure proper alignment on the stack. On aarch64, it has to be 16
pid = clone(childEntry, stack + sizeof(stack) - 16, flags, this); bytes. */
#else pid = clone(childEntry,
pid = clone(childEntry, stack + sizeof(stack) - 8, flags, this); (char *)(((uintptr_t)stack + sizeof(stack) - 8) & ~(uintptr_t)0xf),
#endif flags, this);
if (pid == -1) if (pid == -1)
throw SysError("cloning builder process"); throw SysError("cloning builder process");
} else } else