Commit 2abbcc09 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Andrew Morton
Browse files

uprobes: turn xol_area->pages[2] into xol_area->page 

Now that xol_mapping has its own ->fault() method we no longer need
xol_area->pages[1] == NULL, we need a single page.

Link: https://lkml.kernel.org/r/20240911131437.GC3448@redhat.com


Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 6d27a31e

kernel/events/uprobes.c

+8 −9
Original line number Diff line number Diff line
@@ -99,7 +99,7 @@ struct xol_area { 
	atomic_t 			slot_count;	/* number of in-use slots */

	unsigned long 			*bitmap;	/* 0 = free slot */



	struct page 			*pages[2];

	struct page			*page;

	/*

	 * We keep the vma's vm_start rather than a pointer to the vma

	 * itself.  The probed process or a naughty kernel module could make
@@ -1437,7 +1437,7 @@ static vm_fault_t xol_fault(const struct vm_special_mapping *sm, 
{

	struct xol_area *area = vma->vm_mm->uprobes_state.xol_area;



	vmf->page = area->pages[0];

	vmf->page = area->page;

	get_page(vmf->page);

	return 0;

}
@@ -1512,10 +1512,9 @@ static struct xol_area *__create_xol_area(unsigned long vaddr) 
	if (!area->bitmap)

		goto free_area;



	area->pages[0] = alloc_page(GFP_HIGHUSER);

	if (!area->pages[0])

	area->page = alloc_page(GFP_HIGHUSER);

	if (!area->page)

		goto free_bitmap;

	area->pages[1] = NULL;



	area->vaddr = vaddr;

	init_waitqueue_head(&area->wq);
@@ -1523,12 +1522,12 @@ static struct xol_area *__create_xol_area(unsigned long vaddr) 
	set_bit(0, area->bitmap);

	atomic_set(&area->slot_count, 1);

	insns = arch_uprobe_trampoline(&insns_size);

	arch_uprobe_copy_ixol(area->pages[0], 0, insns, insns_size);

	arch_uprobe_copy_ixol(area->page, 0, insns, insns_size);



	if (!xol_add_vma(mm, area))

		return area;



	__free_page(area->pages[0]);

	__free_page(area->page);

 free_bitmap:

	kfree(area->bitmap);

 free_area:
@@ -1570,7 +1569,7 @@ void uprobe_clear_state(struct mm_struct *mm) 
	if (!area)

		return;



	put_page(area->pages[0]);

	put_page(area->page);

	kfree(area->bitmap);

	kfree(area);

}
@@ -1637,7 +1636,7 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe) 
	if (unlikely(!xol_vaddr))

		return 0;



	arch_uprobe_copy_ixol(area->pages[0], xol_vaddr,

	arch_uprobe_copy_ixol(area->page, xol_vaddr,

			      &uprobe->arch.ixol, sizeof(uprobe->arch.ixol));



	return xol_vaddr;