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Commit e8ed11b9 authored by Daniel Jacobowitz's avatar Daniel Jacobowitz Committed by Linus Torvalds
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[PATCH] x86_64: fix 32-bit thread debugging 



The IA32 ptrace emulation currently returns the wrong registers for fs/gs;
it's returning what x86_64 calls gs_base.  We need regs.gsindex in order
for GDB to correctly locate the TLS area.  Without this patch, the 32-bit
GDB testsuite bombs on a 64-bit kernel.  With it, results look about like
I'd expect, although there are still a handful of kernel-related failures
(vsyscall related?).

Signed-off-by: default avatarDaniel Jacobowitz <dan@codesourcery.com>
Acked-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c91096d8

arch/x86_64/ia32/ptrace32.c

+4 −4
Original line number Diff line number Diff line
@@ -43,11 +43,11 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 val) 
	switch (regno) {

	case offsetof(struct user32, regs.fs):

		if (val && (val & 3) != 3) return -EIO; 

		child->thread.fs = val & 0xffff; 

		child->thread.fsindex = val & 0xffff;

		break;

	case offsetof(struct user32, regs.gs):

		if (val && (val & 3) != 3) return -EIO; 

		child->thread.gs = val & 0xffff;

		child->thread.gsindex = val & 0xffff;

		break;

	case offsetof(struct user32, regs.ds):

		if (val && (val & 3) != 3) return -EIO;
@@ -138,10 +138,10 @@ static int getreg32(struct task_struct *child, unsigned regno, u32 *val) 


	switch (regno) {

	case offsetof(struct user32, regs.fs):

	        *val = child->thread.fs; 

	        *val = child->thread.fsindex;

		break;

	case offsetof(struct user32, regs.gs):

		*val = child->thread.gs;

		*val = child->thread.gsindex;

		break;

	case offsetof(struct user32, regs.ds):

		*val = child->thread.ds;