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uprobes: Add the "enum rp_check ctx" arg to arch_uretprobe_is_alive() 

arch/x86 doesn't care (so far), but as Pratyush Anand pointed
out other architectures might want why arch_uretprobe_is_alive()
was called and use different checks depending on the context.
Add the new argument to distinguish 2 callers.

Tested-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Anton Arapov <arapov@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150721134026.GA4779@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Oleg Nesterov 2015-07-21 15:40:26 +02:00 committed by Ingo Molnar
parent a5b7e1a89b
commit 86dcb702e7
3 changed files with 14 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/x86/kernel/uprobes.c
View File

@ -986,7 +986,8 @@ arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs
return -1;
}
bool arch_uretprobe_is_alive(struct return_instance *ret, struct pt_regs *regs)
bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
struct pt_regs *regs)
{
return regs->sp <= ret->stack;
}

7
include/linux/uprobes.h
View File

@ -102,6 +102,11 @@ struct return_instance {
struct return_instance *next; /* keep as stack */
};
enum rp_check {
RP_CHECK_CALL,
RP_CHECK_RET,
};
struct xol_area;
struct uprobes_state {
@ -138,7 +143,7 @@ extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk);
extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data);
extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs);
extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs);
extern bool arch_uretprobe_is_alive(struct return_instance *ret, struct pt_regs *regs);
extern bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx, struct pt_regs *regs);
extern bool arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs);
extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
void *src, unsigned long len);

9
kernel/events/uprobes.c
View File

@ -1514,7 +1514,9 @@ static unsigned long get_trampoline_vaddr(void)
static void cleanup_return_instances(struct uprobe_task *utask, struct pt_regs *regs)
{
struct return_instance *ri = utask->return_instances;
while (ri && !arch_uretprobe_is_alive(ri, regs)) {
enum rp_check ctx = RP_CHECK_CALL;
while (ri && !arch_uretprobe_is_alive(ri, ctx, regs)) {
ri = free_ret_instance(ri);
utask->depth--;
}
@ -1805,7 +1807,7 @@ static void handle_trampoline(struct pt_regs *regs)
* could hit this trampoline on return. TODO: sigaltstack().
*/
next = find_next_ret_chain(ri);
valid = !next || arch_uretprobe_is_alive(next, regs);
valid = !next || arch_uretprobe_is_alive(next, RP_CHECK_RET, regs);
instruction_pointer_set(regs, ri->orig_ret_vaddr);
do {
@ -1830,7 +1832,8 @@ bool __weak arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs)
return false;
}
bool __weak arch_uretprobe_is_alive(struct return_instance *ret, struct pt_regs *regs)
bool __weak arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
struct pt_regs *regs)
{
return true;
}