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| author |   Oleg Nesterov <oleg@redhat.com> | 2012-06-15 17:43:50 +0200 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2012-06-16 09:10:47 +0200 |
| commit | d9c4a30e82614d43b55893a73f31e7284007ce82 (patch) | |
| tree | b877ed2338d27237e40b2587cdf9e6cd56fefe57 /kernel | |
| parent | uprobes: No need to re-check vma_address() in write_opcode() (diff) | |
| download | linux-dev-d9c4a30e82614d43b55893a73f31e7284007ce82.tar.xz linux-dev-d9c4a30e82614d43b55893a73f31e7284007ce82.zip | |
uprobes: Move BUG_ON(UPROBE_SWBP_INSN_SIZE) from write_opcode() to install_breakpoint()
write_opcode() ensures that UPROBE_SWBP_INSN doesn't cross the
page boundary. This looks a bit confusing, the check does not
depend on vaddr and it is enough to do it only once right after
install_breakpoint()->arch_uprobe_analyze_insn().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154350.GA9611@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/uprobes.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 14c71a2aadad..b9c61bda9029 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -210,7 +210,6 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, void *vaddr_old, *vaddr_new; struct vm_area_struct *vma; struct uprobe *uprobe; - unsigned long pgoff; int ret; retry: /* Read the page with vaddr into memory */ @@ -251,11 +250,7 @@ retry: vaddr_new = kmap_atomic(new_page); memcpy(vaddr_new, vaddr_old, PAGE_SIZE); - - /* poke the new insn in, ASSUMES we don't cross page boundary */ - pgoff = (vaddr & ~PAGE_MASK); - BUG_ON(pgoff + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); - memcpy(vaddr_new + pgoff, &opcode, UPROBE_SWBP_INSN_SIZE); + memcpy(vaddr_new + (vaddr & ~PAGE_MASK), &opcode, UPROBE_SWBP_INSN_SIZE); kunmap_atomic(vaddr_new); kunmap_atomic(vaddr_old); @@ -699,6 +694,10 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, if (ret) return ret; + /* write_opcode() assumes we don't cross page boundary */ + BUG_ON((uprobe->offset & ~PAGE_MASK) + + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); + uprobe->flags |= UPROBE_COPY_INSN; } |