Messages in this thread | | | Date | Fri, 2 Jul 2010 16:18:05 -0600 | Subject | 2.6.34 rex64 sysret instruction setup not preserving flags (r11 contents and eflags do not match) | From | Jeffrey Merkey <> |
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On an AMD64 based system executing int 1 exceptions across a rex64 sysret, if the debugger sets the trap flag, r11 which holds the eflags values for the sysret return from syscall, the flags do not appear to get set resutling in the int exception nesting by calling sysret over and over again until the kernel stack runs off the end. Looks like the resume did not get set on this instruction.
sysret on AMD requires the flags be saved into r11 and what I am seeing is the flags not matching what has been set in the pt_regs struct.
Jeff
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