Date: Tue, 8 Jun 2021 13:38:04 GMT From: Mark Johnston <markj@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: cb5fe9aa9fa0 - stable/13 - amd64: Clear the local TSS when creating a new thread Message-ID: <202106081338.158Dc4tL074974@gitrepo.freebsd.org>
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The branch stable/13 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=cb5fe9aa9fa0376078abc173b27605b6096dc681 commit cb5fe9aa9fa0376078abc173b27605b6096dc681 Author: Mark Johnston <markj@FreeBSD.org> AuthorDate: 2021-06-01 23:38:22 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2021-06-08 13:33:59 +0000 amd64: Clear the local TSS when creating a new thread Otherwise it is copied from the creating thread. Then, if either thread exits, the other is left with a dangling pointer, typically resulting in a page fault upon the next context switch. Reported by: syzkaller Reviewed by: kib Sponsored by: The FreeBSD Foundation (cherry picked from commit 8cd05b883330049d536a40e2f4c9ff92d0e6944e) --- sys/amd64/amd64/vm_machdep.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/sys/amd64/amd64/vm_machdep.c b/sys/amd64/amd64/vm_machdep.c index 1acc5dc55c85..7d65269410e0 100644 --- a/sys/amd64/amd64/vm_machdep.c +++ b/sys/amd64/amd64/vm_machdep.c @@ -189,6 +189,8 @@ copy_thread(struct thread *td1, struct thread *td2) * pcb2->pcb_[fg]sbase: cloned above */ + pcb2->pcb_tssp = NULL; + /* Setup to release spin count in fork_exit(). */ td2->td_md.md_spinlock_count = 1; td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
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