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Fix a race condition introduced when redzones were added. Use an

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atomic operation to return and adjust the stack.

Submitted by:	luoqi
This commit is contained in:
Daniel Eischen 2006-02-24 22:03:10 +00:00
parent 33499e2ae5
commit c0addafac3
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=155990
2 changed files with 8 additions and 10 deletions
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9
lib/libkse/arch/amd64/amd64/context.S
View file

@ -162,11 +162,11 @@ ENTRY(_amd64_restore_context)
cmpq $0, %rdi /* check for null pointer */ cmpq $0, %rdi /* check for null pointer */
jne 1f jne 1f
movq $-1, %rax movq $-1, %rax
jmp 7f jmp 2f
1: cmpq $MC_SIZE, MC_LEN_OFFSET(%rdi) /* is context valid? */ 1: cmpq $MC_SIZE, MC_LEN_OFFSET(%rdi) /* is context valid? */
je 2f je 2f
movq $-1, %rax /* bzzzt, invalid context */ movq $-1, %rax /* bzzzt, invalid context */
jmp 7f ret
2: movq MC_RCX(%rdi), %rcx 2: movq MC_RCX(%rdi), %rcx
movq MC_R8(%rdi), %r8 movq MC_R8(%rdi), %r8
movq MC_R9(%rdi), %r9 movq MC_R9(%rdi), %r9
@ -213,6 +213,5 @@ ENTRY(_amd64_restore_context)
popq %rsi /* restore rsi, rdx, and rdi */ popq %rsi /* restore rsi, rdx, and rdi */
popq %rdx popq %rdx
popq %rdi popq %rdi
leaq (8 + REDZONE)(%rsp), %rsp ret $REDZONE
jmp *-(8 + REDZONE)(%rsp) /* jump to return address */
7: ret

9
lib/libpthread/arch/amd64/amd64/context.S
View file

@ -162,11 +162,11 @@ ENTRY(_amd64_restore_context)
cmpq $0, %rdi /* check for null pointer */ cmpq $0, %rdi /* check for null pointer */
jne 1f jne 1f
movq $-1, %rax movq $-1, %rax
jmp 7f jmp 2f
1: cmpq $MC_SIZE, MC_LEN_OFFSET(%rdi) /* is context valid? */ 1: cmpq $MC_SIZE, MC_LEN_OFFSET(%rdi) /* is context valid? */
je 2f je 2f
movq $-1, %rax /* bzzzt, invalid context */ movq $-1, %rax /* bzzzt, invalid context */
jmp 7f ret
2: movq MC_RCX(%rdi), %rcx 2: movq MC_RCX(%rdi), %rcx
movq MC_R8(%rdi), %r8 movq MC_R8(%rdi), %r8
movq MC_R9(%rdi), %r9 movq MC_R9(%rdi), %r9
@ -213,6 +213,5 @@ ENTRY(_amd64_restore_context)
popq %rsi /* restore rsi, rdx, and rdi */ popq %rsi /* restore rsi, rdx, and rdi */
popq %rdx popq %rdx
popq %rdi popq %rdi
leaq (8 + REDZONE)(%rsp), %rsp ret $REDZONE
jmp *-(8 + REDZONE)(%rsp) /* jump to return address */
7: ret