linux-kernel - [PATCH v3 04/14] uprobes: Change prepare_uretprobe() to use uprobe

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Message-ID: <20150721134010.GA4752@redhat.com>
Date:	Tue, 21 Jul 2015 15:40:10 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Andy Lutomirski <luto@...capital.net>,
	Pratyush Anand <panand@...hat.com>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH v3 04/14] uprobes: Change prepare_uretprobe() to use
	uprobe_warn()

Turn the last pr_warn() in uprobes.c into uprobe_warn().

While at it:

   - s/kzalloc/kmalloc, we initialize every member of ri

   - remove the pointless comment above the obvious code

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
Acked-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Acked-by: Anton Arapov <arapov@...il.com>
Tested-by: Pratyush Anand <panand@...hat.com>
---
 kernel/events/uprobes.c |   10 +++-------
 1 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index eabdc21..4c941fe 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1541,9 +1541,9 @@ static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs)
 		return;
 	}
 
-	ri = kzalloc(sizeof(struct return_instance), GFP_KERNEL);
+	ri = kmalloc(sizeof(struct return_instance), GFP_KERNEL);
 	if (!ri)
-		goto fail;
+		return;
 
 	trampoline_vaddr = get_trampoline_vaddr();
 	orig_ret_vaddr = arch_uretprobe_hijack_return_addr(trampoline_vaddr, regs);
@@ -1561,8 +1561,7 @@ static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs)
 			 * This situation is not possible. Likely we have an
 			 * attack from user-space.
 			 */
-			pr_warn("uprobe: unable to set uretprobe pid/tgid=%d/%d\n",
-						current->pid, current->tgid);
+			uprobe_warn(current, "handle tail call");
 			goto fail;
 		}
 
@@ -1576,13 +1575,10 @@ static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs)
 	ri->chained = chained;
 
 	utask->depth++;
-
-	/* add instance to the stack */
 	ri->next = utask->return_instances;
 	utask->return_instances = ri;
 
 	return;
-
  fail:
 	kfree(ri);
 }
-- 
1.5.5.1

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