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Commit cf6f196d authored by Jason Wessel's avatar Jason Wessel
Browse files

kgdb,i386: Fix corner case access to ss with NMI watch dog exception 



It is possible for the user_mode_vm(regs) check to return true on the
i368 arch for a non master kgdb cpu or when the master kgdb cpu
handles the NMI watch dog exception.

The solution is simply to select the correct gdb_ss location
based on the check to user_mode_vm(regs).

CC: Ingo Molnar <mingo@elte.hu>
Acked-by: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
parent 59d309f9

arch/x86/kernel/kgdb.c

+8 −2
Original line number Diff line number Diff line
@@ -86,9 +86,15 @@ void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) 
	gdb_regs[GDB_DS]	= regs->ds;

	gdb_regs[GDB_ES]	= regs->es;

	gdb_regs[GDB_CS]	= regs->cs;

	gdb_regs[GDB_SS]	= __KERNEL_DS;

	gdb_regs[GDB_FS]	= 0xFFFF;

	gdb_regs[GDB_GS]	= 0xFFFF;

	if (user_mode_vm(regs)) {

		gdb_regs[GDB_SS] = regs->ss;

		gdb_regs[GDB_SP] = regs->sp;

	} else {

		gdb_regs[GDB_SS] = __KERNEL_DS;

		gdb_regs[GDB_SP] = kernel_stack_pointer(regs);

	}

#else

	gdb_regs[GDB_R8]	= regs->r8;

	gdb_regs[GDB_R9]	= regs->r9;
@@ -101,8 +107,8 @@ void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) 
	gdb_regs32[GDB_PS]	= regs->flags;

	gdb_regs32[GDB_CS]	= regs->cs;

	gdb_regs32[GDB_SS]	= regs->ss;

#endif

	gdb_regs[GDB_SP]	= kernel_stack_pointer(regs);

#endif

}



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