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authorSong Liu <songliubraving@fb.com>2018-04-23 10:21:35 -0700
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-04-26 14:50:56 -0400
commit61f94203c9efcaf44a7435298697caf406476c79 (patch)
tree28dbde5c548085dfae5eaef1484ef8e2b56db2d6 /kernel/events
parent0c92c7a3c5d416f47b32c5f20a611dfeca5d5f2e (diff)
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tracing: Remove igrab() iput() call from uprobes.c
Caller of uprobe_register is required to keep the inode and containing mount point referenced. There was misuse of igrab() in uprobes.c and trace_uprobe.c. This is because igrab() will not prevent umount of the containing mount point. To fix this, we added path to struct trace_uprobe, which keeps the inode and containing mount reference. For uprobes.c, it is not necessary to call igrab() in uprobe_register(), as the caller is required to keep the inode reference. The igrab() is removed and comments on this requirement is added to uprobe_register(). Link: http://lkml.kernel.org/r/CAELBmZB2XX=qEOLAdvGG4cPx4GEntcSnWQquJLUK1ongRj35cA@mail.gmail.com Link: http://lkml.kernel.org/r/20180423172135.4050588-2-songliubraving@fb.com Cc: Ingo Molnar <mingo@redhat.com> Cc: Howard McLauchlan <hmclauchlan@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/uprobes.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index ce6848e46e94..1725b902983f 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -491,7 +491,7 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
if (!uprobe)
return NULL;
- uprobe->inode = igrab(inode);
+ uprobe->inode = inode;
uprobe->offset = offset;
init_rwsem(&uprobe->register_rwsem);
init_rwsem(&uprobe->consumer_rwsem);
@@ -502,7 +502,6 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
if (cur_uprobe) {
kfree(uprobe);
uprobe = cur_uprobe;
- iput(inode);
}
return uprobe;
@@ -701,7 +700,6 @@ static void delete_uprobe(struct uprobe *uprobe)
rb_erase(&uprobe->rb_node, &uprobes_tree);
spin_unlock(&uprobes_treelock);
RB_CLEAR_NODE(&uprobe->rb_node); /* for uprobe_is_active() */
- iput(uprobe->inode);
put_uprobe(uprobe);
}
@@ -873,7 +871,8 @@ static void __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *u
* tuple). Creation refcount stops uprobe_unregister from freeing the
* @uprobe even before the register operation is complete. Creation
* refcount is released when the last @uc for the @uprobe
- * unregisters.
+ * unregisters. Caller of uprobe_register() is required to keep @inode
+ * (and the containing mount) referenced.
*
* Return errno if it cannot successully install probes
* else return 0 (success)