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Subject[tip:perf/core] uprobes: Copy_insn() shouldn't depend on mm/vma/ vaddr
Commit-ID:  d436615e60c386095dac4a9bf72b08868d2a7564
Gitweb: http://git.kernel.org/tip/d436615e60c386095dac4a9bf72b08868d2a7564
Author: Oleg Nesterov <oleg@redhat.com>
AuthorDate: Fri, 15 Jun 2012 17:43:42 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Sat, 16 Jun 2012 09:10:45 +0200

uprobes: Copy_insn() shouldn't depend on mm/vma/vaddr

1. copy_insn() doesn't need "addr", it can use uprobe->offset.
Remove this argument.

2. Change copy_insn/__copy_insn to accept "struct file*" instead
of vma.

copy_insn() is called only once and mm/vma/vaddr are random, it
shouldn't depend on them.

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/20120615154342.GA9598@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/events/uprobes.c | 15 ++++++---------
1 files changed, 6 insertions(+), 9 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 2671d9a..08ef566 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -591,10 +591,9 @@ static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc)
}

static int
-__copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *insn,
+__copy_insn(struct address_space *mapping, struct file *filp, char *insn,
unsigned long nbytes, unsigned long offset)
{
- struct file *filp = vma->vm_file;
struct page *page;
void *vaddr;
unsigned long off1;
@@ -625,15 +624,13 @@ __copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *ins
return 0;
}

-static int
-copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr)
+static int copy_insn(struct uprobe *uprobe, struct file *filp)
{
struct address_space *mapping;
unsigned long nbytes;
int bytes;

- addr &= ~PAGE_MASK;
- nbytes = PAGE_SIZE - addr;
+ nbytes = PAGE_SIZE - (uprobe->offset & ~PAGE_MASK);
mapping = uprobe->inode->i_mapping;

/* Instruction at end of binary; copy only available bytes */
@@ -644,13 +641,13 @@ copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr)

/* Instruction at the page-boundary; copy bytes in second page */
if (nbytes < bytes) {
- if (__copy_insn(mapping, vma, uprobe->arch.insn + nbytes,
+ if (__copy_insn(mapping, filp, uprobe->arch.insn + nbytes,
bytes - nbytes, uprobe->offset + nbytes))
return -ENOMEM;

bytes = nbytes;
}
- return __copy_insn(mapping, vma, uprobe->arch.insn, bytes, uprobe->offset);
+ return __copy_insn(mapping, filp, uprobe->arch.insn, bytes, uprobe->offset);
}

/*
@@ -696,7 +693,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
addr = (unsigned long)vaddr;

if (!(uprobe->flags & UPROBE_COPY_INSN)) {
- ret = copy_insn(uprobe, vma, addr);
+ ret = copy_insn(uprobe, vma->vm_file);
if (ret)
return ret;


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