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authorOleg Nesterov <oleg@redhat.com>2012-08-06 14:49:56 +0200
committerAnton Arapov <anton@redhat.com>2012-10-29 11:42:34 +0100
commitd32bf52227cd91de2988643210563534ce92759f (patch)
tree51b16623ed95189718ffff117f219479e7fec867
parent1b3001711bcdfdd1ef83b264334dddf17f2b9055 (diff)
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uprobes: Change uprobe_mmap() to ignore the errors but check fatal_signal_pending()
Once install_breakpoint() fails uprobe_mmap() "ignores" all other uprobes and returns the error. It was never really needed to to stop after the first error, and in fact it was always wrong at least in -ENOTSUPP case. Change uprobe_mmap() to ignore the errors and always return 0. This is not what we want in the long term, but until we teach the callers to handle the failure it would be better to remove the pointless complications. And this doesn't look too bad, the only "reasonable" error is ENOMEM but in this case the caller should be oom-killed in the likely case or the system has more serious problems. However it makes sense to stop if fatal_signal_pending() == T. In particular this helps if the task was oom-killed. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
-rw-r--r--kernel/events/uprobes.c27
1 files changed, 6 insertions, 21 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index ce59c10..298fbbd 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -994,23 +994,16 @@ static void build_probe_list(struct inode *inode,
}
/*
- * Called from mmap_region.
- * called with mm->mmap_sem acquired.
+ * Called from mmap_region/vma_adjust with mm->mmap_sem acquired.
*
- * Return -ve no if we fail to insert probes and we cannot
- * bail-out.
- * Return 0 otherwise. i.e:
- *
- * - successful insertion of probes
- * - (or) no possible probes to be inserted.
- * - (or) insertion of probes failed but we can bail-out.
+ * Currently we ignore all errors and always return 0, the callers
+ * can't handle the failure anyway.
*/
int uprobe_mmap(struct vm_area_struct *vma)
{
struct list_head tmp_list;
struct uprobe *uprobe, *u;
struct inode *inode;
- int ret;
if (!atomic_read(&uprobe_events) || !valid_vma(vma, true))
return 0;
@@ -1022,24 +1015,16 @@ int uprobe_mmap(struct vm_area_struct *vma)
mutex_lock(uprobes_mmap_hash(inode));
build_probe_list(inode, vma, vma->vm_start, vma->vm_end, &tmp_list);
- ret = 0;
list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
- if (!ret) {
+ if (!fatal_signal_pending(current)) {
unsigned long vaddr = offset_to_vaddr(vma, uprobe->offset);
-
- ret = install_breakpoint(uprobe, vma->vm_mm, vma, vaddr);
- /*
- * We can race against uprobe_register(), see the
- * comment near uprobe_hash().
- */
- if (ret == -EEXIST)
- ret = 0;
+ install_breakpoint(uprobe, vma->vm_mm, vma, vaddr);
}
put_uprobe(uprobe);
}
mutex_unlock(uprobes_mmap_hash(inode));
- return ret;
+ return 0;
}
/*