Commit-ID: d9c4a30e82614d43b55893a73f31e7284007ce82 Gitweb: http://git.kernel.org/tip/d9c4a30e82614d43b55893a73f31e7284007ce82 Author: Oleg Nesterov <oleg@xxxxxxxxxx> AuthorDate: Fri, 15 Jun 2012 17:43:50 +0200 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Sat, 16 Jun 2012 09:10:47 +0200 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@xxxxxxxxxx> Acked-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx> Acked-by: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx> Cc: Anton Arapov <anton@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/20120615154350.GA9611@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- 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 14c71a2..b9c61bd 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; } -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
|