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Disable local interrupts before testing the PCB_FULL_IRET flag.

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Thread might be preempted after testing, which causes the flag to be
cleared. If ast was not delivered, we will do sysret with potentially
wrong fs/gs bases.

Reviewed by:	jhb, jkim
MFC after:	1 week (together with r220430, r220452)
This commit is contained in:
Konstantin Belousov 2011-04-08 21:26:50 +00:00
parent 80c2cdcffe
commit 5ab73cbcba
1 changed files with 2 additions and 1 deletions
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3
sys/amd64/amd64/exception.S
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@ -383,10 +383,11 @@ IDTVEC(fast_syscall)
movq %rsp,%rdi
call syscall
1: movq PCPU(CURPCB),%rax
/* Disable interrupts before testing PCB_FULL_IRET. */
cli
testl $PCB_FULL_IRET,PCB_FLAGS(%rax)
jnz 3f
/* Check for and handle AST's on return to userland. */
cli
movq PCPU(CURTHREAD),%rax
testl $TDF_ASTPENDING | TDF_NEEDRESCHED,TD_FLAGS(%rax)
je 2f