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| author | kib <kib@FreeBSD.org> | 2010-05-12 10:29:35 +0000 |
|---|---|---|
| committer | kib <kib@FreeBSD.org> | 2010-05-12 10:29:35 +0000 |
| commit | 7c190c1c89d45ca83db4120a8a5fe107a8a52050 (patch) | |
| tree | eecf228988f4249cfce539021a39a53ebe7b9b01 /sys/amd64/amd64/exception.S | |
| parent | 7b04e359b060fb4d6869ca817495df9327ef6090 (diff) | |
| download | FreeBSD-src-7c190c1c89d45ca83db4120a8a5fe107a8a52050.zip FreeBSD-src-7c190c1c89d45ca83db4120a8a5fe107a8a52050.tar.gz | |
Route all returns from the interrupts and faults through the doreti_iret
labeled iretq instruction.
Suppose that multithreaded process executes two threads, currently
scheduled on different processors. Let assume that thread A executes
using %cs or %ss pointing into the descriptor from LDT. If IPI comes
which handler does not return by jump to doreti, and meantime thread B
invalidates descriptor pointed to by %cs or %ss, then iretq from IPI
handler could fault.
Routing the return by doreti_iret allows kernel to catch the situation
and recover from it by sending signal to the usermode.
Tested by: pho
MFC after: 1 week
Diffstat (limited to 'sys/amd64/amd64/exception.S')
| -rw-r--r-- | sys/amd64/amd64/exception.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sys/amd64/amd64/exception.S b/sys/amd64/amd64/exception.S index 7b1fed8..d18fb0d 100644 --- a/sys/amd64/amd64/exception.S +++ b/sys/amd64/amd64/exception.S @@ -553,7 +553,7 @@ nmi_restoreregs: movq TF_R14(%rsp),%r14 movq TF_R15(%rsp),%r15 addq $TF_RIP,%rsp - iretq + jmp doreti_iret ENTRY(fork_trampoline) movq %r12,%rdi /* function */ |
