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x86: kretprobe-booster interrupt emulation code fix

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Fix interrupt emulation code in kretprobe-booster according to
pt_regs update (es/ds change and gs adding).

This issue has been reported on systemtap-bugzilla:

  http://sources.redhat.com/bugzilla/show_bug.cgi?id=9965

  | On a -tip kernel on x86_32, kretprobe_example (from samples) triggers the
  | following backtrace when its retprobing a class of functions that cause a
  | copy_from/to_user().
  |
  | BUG: sleeping function called from invalid context at mm/memory.c:3196
  | in_atomic(): 0, irqs_disabled(): 1, pid: 2286, name: cat

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Tested-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: systemtap-ml <systemtap@sources.redhat.com>
LKML-Reference: <49C7995C.2010601@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Masami Hiramatsu 2009-03-23 10:14:52 -04:00 committed by Ingo Molnar
parent a524446fe8
commit fee039a1d0
1 changed files with 9 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
arch/x86/kernel/kprobes.c
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@ -638,13 +638,13 @@ static void __used __kprobes kretprobe_trampoline_holder(void)
#else
" pushf\n"
/*
* Skip cs, ip, orig_ax.
* Skip cs, ip, orig_ax and gs.
* trampoline_handler() will plug in these values
*/
" subl $12, %esp\n"
" subl $16, %esp\n"
" pushl %fs\n"
" pushl %ds\n"
" pushl %es\n"
" pushl %ds\n"
" pushl %eax\n"
" pushl %ebp\n"
" pushl %edi\n"
@ -655,10 +655,10 @@ static void __used __kprobes kretprobe_trampoline_holder(void)
" movl %esp, %eax\n"
" call trampoline_handler\n"
/* Move flags to cs */
" movl 52(%esp), %edx\n"
" movl %edx, 48(%esp)\n"
" movl 56(%esp), %edx\n"
" movl %edx, 52(%esp)\n"
/* Replace saved flags with true return address. */
" movl %eax, 52(%esp)\n"
" movl %eax, 56(%esp)\n"
" popl %ebx\n"
" popl %ecx\n"
" popl %edx\n"
@ -666,8 +666,8 @@ static void __used __kprobes kretprobe_trampoline_holder(void)
" popl %edi\n"
" popl %ebp\n"
" popl %eax\n"
/* Skip ip, orig_ax, es, ds, fs */
" addl $20, %esp\n"
/* Skip ds, es, fs, gs, orig_ax and ip */
" addl $24, %esp\n"
" popf\n"
#endif
" ret\n");
@ -691,6 +691,7 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
regs->cs = __KERNEL_CS;
#else
regs->cs = __KERNEL_CS | get_kernel_rpl();
regs->gs = 0;
#endif
regs->ip = trampoline_address;
regs->orig_ax = ~0UL;