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Revert "[PATCH] x86-64: Fix up handling of non canonical user RIPs"
This reverts commit c33d4568ac
.
Andrew Clayton and Hugh Dickins report that it's broken for them and
causes strange page table and slab corruption, and spontaneous reboots.
Let's get it right next time.
Cc: Andrew Clayton <andrew@rootshell.co.uk>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
parent
ceb2ca9cb0
commit
cbf0ec6ee0
@ -178,12 +178,6 @@ rff_trace:
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* Interrupts are off on entry.
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* Only called from user space.
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*
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* EM64T CPUs have somewhat weird error reporting for non canonical RIPs in SYSRET.
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* We can't handle any exceptions there because the exception handler would
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* end up running on the user stack which is unsafe. To avoid problems
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* any code that might end up with a user touched pt_regs should return
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* using int_ret_from_syscall.
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*
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* XXX if we had a free scratch register we could save the RSP into the stack frame
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* and report it properly in ps. Unfortunately we haven't.
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*/
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@ -260,9 +254,7 @@ sysret_signal:
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xorl %esi,%esi # oldset -> arg2
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call ptregscall_common
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1: movl $_TIF_NEED_RESCHED,%edi
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/* Stack frame might have been changed. The IRET path does
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some additional checks to handle this */
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jmp int_with_check
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jmp sysret_check
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badsys:
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movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
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@ -288,8 +280,7 @@ tracesys:
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call syscall_trace_leave
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RESTORE_TOP_OF_STACK %rbx
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RESTORE_REST
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/* Stack frame might have been changed. Use the more careful IRET path */
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jmp int_ret_from_sys_call
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jmp ret_from_sys_call
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CFI_ENDPROC
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/*
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@ -417,9 +408,25 @@ ENTRY(stub_execve)
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CFI_ADJUST_CFA_OFFSET -8
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CFI_REGISTER rip, r11
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SAVE_REST
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movq %r11, %r15
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CFI_REGISTER rip, r15
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FIXUP_TOP_OF_STACK %r11
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call sys_execve
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GET_THREAD_INFO(%rcx)
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bt $TIF_IA32,threadinfo_flags(%rcx)
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CFI_REMEMBER_STATE
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jc exec_32bit
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RESTORE_TOP_OF_STACK %r11
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movq %r15, %r11
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CFI_REGISTER rip, r11
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RESTORE_REST
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pushq %r11
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CFI_ADJUST_CFA_OFFSET 8
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CFI_REL_OFFSET rip, 0
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ret
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exec_32bit:
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CFI_RESTORE_STATE
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movq %rax,RAX(%rsp)
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RESTORE_REST
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jmp int_ret_from_sys_call
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