diff options
| author | Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> | 2006-11-08 17:44:49 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-11-08 18:29:24 -0800 |
| commit | 8bdc052eccdc7893d075d3f1f7103594a458c8c4 (patch) | |
| tree | 33bc012cebe8c3e012c533aade5e9d6ced34cce0 /arch/i386 | |
| parent | 4b438a23fb05b6566393f9f0a3987ea3dcc1c0c4 (diff) | |
| download | lwn-8bdc052eccdc7893d075d3f1f7103594a458c8c4.tar.gz lwn-8bdc052eccdc7893d075d3f1f7103594a458c8c4.zip | |
[PATCH] kretprobe: fix kretprobe-booster to save regs and set status
There are two bugs in the kretprobe-booster.
1) It doesn't make room for gs registers.
2) It doesn't change status of the current kprobe. This status will
effect the fault handling.
This patch fixes these bugs and, additionally, saves skipped registers for
compatibility with the original kretprobe.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386')
| -rw-r--r-- | arch/i386/kernel/kprobes.c | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c index d98e44b16fe2..fc79e1e859c4 100644 --- a/arch/i386/kernel/kprobes.c +++ b/arch/i386/kernel/kprobes.c @@ -361,8 +361,11 @@ no_kprobe: asm volatile ( ".global kretprobe_trampoline\n" "kretprobe_trampoline: \n" " pushf\n" - /* skip cs, eip, orig_eax, es, ds */ - " subl $20, %esp\n" + /* skip cs, eip, orig_eax */ + " subl $12, %esp\n" + " pushl %gs\n" + " pushl %ds\n" + " pushl %es\n" " pushl %eax\n" " pushl %ebp\n" " pushl %edi\n" @@ -373,10 +376,10 @@ no_kprobe: " movl %esp, %eax\n" " call trampoline_handler\n" /* move eflags to cs */ - " movl 48(%esp), %edx\n" - " movl %edx, 44(%esp)\n" + " movl 52(%esp), %edx\n" + " movl %edx, 48(%esp)\n" /* save true return address on eflags */ - " movl %eax, 48(%esp)\n" + " movl %eax, 52(%esp)\n" " popl %ebx\n" " popl %ecx\n" " popl %edx\n" @@ -384,8 +387,8 @@ no_kprobe: " popl %edi\n" " popl %ebp\n" " popl %eax\n" - /* skip eip, orig_eax, es, ds */ - " addl $16, %esp\n" + /* skip eip, orig_eax, es, ds, gs */ + " addl $20, %esp\n" " popf\n" " ret\n"); } @@ -404,6 +407,10 @@ fastcall void *__kprobes trampoline_handler(struct pt_regs *regs) INIT_HLIST_HEAD(&empty_rp); spin_lock_irqsave(&kretprobe_lock, flags); head = kretprobe_inst_table_head(current); + /* fixup registers */ + regs->xcs = __KERNEL_CS; + regs->eip = trampoline_address; + regs->orig_eax = 0xffffffff; /* * It is possible to have multiple instances associated with a given @@ -425,6 +432,7 @@ fastcall void *__kprobes trampoline_handler(struct pt_regs *regs) if (ri->rp && ri->rp->handler){ __get_cpu_var(current_kprobe) = &ri->rp->kp; + get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE; ri->rp->handler(ri, regs); __get_cpu_var(current_kprobe) = NULL; } |