From: Oleg Nesterov <oleg@redhat.com>
To: Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Anton Arapov <arapov@gmail.com>,
David Long <dave.long@linaro.org>,
Denys Vlasenko <dvlasenk@redhat.com>,
"Frank Ch. Eigler" <fche@redhat.com>,
Ingo Molnar <mingo@kernel.org>, Jan Willeke <willeke@de.ibm.com>,
Jim Keniston <jkenisto@us.ibm.com>,
Mark Wielaard <mjw@redhat.com>,
Pratyush Anand <panand@redhat.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH 09/10] uprobes: Change prepare_uretprobe() to (try to) flush the dead frames
Date: Mon, 4 May 2015 14:49:22 +0200 [thread overview]
Message-ID: <20150504124922.GA22522@redhat.com> (raw)
In-Reply-To: <20150504124835.GA22462@redhat.com>
Change prepare_uretprobe() to flush the !arch_uretprobe_is_alive()
return_instance's. This is not needed correctness-wise, but can help
to avoid the failure caused by MAX_URETPROBE_DEPTH.
Note: in this case arch_uretprobe_is_alive() can be false positive,
the stack can grow after longjmp(). Unfortunately, the kernel can't
100% solve this problem, but see the next patch.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/events/uprobes.c | 13 +++++++++++++
1 files changed, 13 insertions(+), 0 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 0dd7ff7..b6433fb 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1522,6 +1522,16 @@ static unsigned long get_trampoline_vaddr(void)
return trampoline_vaddr;
}
+static void cleanup_return_instances(struct uprobe_task *utask, struct pt_regs *regs)
+{
+ struct return_instance *ri = utask->return_instances;
+ while (ri && !arch_uretprobe_is_alive(&ri->auret, regs)) {
+ ri = free_ret_instance(ri);
+ utask->depth--;
+ }
+ utask->return_instances = ri;
+}
+
static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs)
{
struct return_instance *ri;
@@ -1576,6 +1586,9 @@ static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs)
ri->orig_ret_vaddr = orig_ret_vaddr;
ri->chained = chained;
+ if (utask->depth) /* drop the entries invalidated by longjmp() */
+ cleanup_return_instances(utask, regs);
+
utask->depth++;
ri->next = utask->return_instances;
utask->return_instances = ri;
--
1.5.5.1
next prev parent reply other threads:[~2015-05-04 12:50 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-04 12:48 [PATCH 00/10] uprobes: longjmp fixes Oleg Nesterov
2015-05-04 12:48 ` [PATCH 01/10] uprobes: Introduce get_uprobe() Oleg Nesterov
2015-05-06 13:20 ` Srikar Dronamraju
2015-05-04 12:48 ` [PATCH 02/10] uprobes: Introduce free_ret_instance() Oleg Nesterov
2015-05-06 13:22 ` Srikar Dronamraju
2015-05-04 12:48 ` [PATCH 03/10] uprobes: Send SIGILL if handle_trampoline() fails Oleg Nesterov
2015-05-06 13:30 ` Srikar Dronamraju
2015-05-04 12:49 ` [PATCH 04/10] uprobes: Change prepare_uretprobe() to use uprobe_warn() Oleg Nesterov
2015-05-07 10:32 ` Srikar Dronamraju
2015-05-04 12:49 ` [PATCH 05/10] uprobes: Change handle_trampoline() to find the next chain beforehand Oleg Nesterov
2015-05-07 10:33 ` Srikar Dronamraju
2015-05-04 12:49 ` [PATCH 06/10] uprobes: Introduce struct arch_uretprobe Oleg Nesterov
2015-05-07 10:34 ` Srikar Dronamraju
2015-05-04 12:49 ` [PATCH 07/10] uprobes/x86: Introduce arch_uretprobe_is_alive() Oleg Nesterov
2015-05-07 10:35 ` Srikar Dronamraju
2015-05-07 11:08 ` Srikar Dronamraju
2015-05-07 17:11 ` Oleg Nesterov
2015-05-08 11:30 ` Srikar Dronamraju
2015-05-10 12:21 ` Oleg Nesterov
2015-05-13 8:11 ` Srikar Dronamraju
2015-05-20 16:51 ` Oleg Nesterov
2015-05-18 12:08 ` Pratyush Anand
2015-05-20 15:51 ` Oleg Nesterov
2015-05-04 12:49 ` [PATCH 08/10] uprobes: Change handle_trampoline() to flush the frames invalidated by longjmp() Oleg Nesterov
2015-05-07 10:38 ` Srikar Dronamraju
2015-05-04 12:49 ` Oleg Nesterov [this message]
2015-05-07 11:19 ` [PATCH 09/10] uprobes: Change prepare_uretprobe() to (try to) flush the dead frames Srikar Dronamraju
2015-06-05 21:40 ` Oleg Nesterov
2015-05-04 12:49 ` [PATCH 10/10] uprobes/x86: Change arch_uretprobe_is_alive() to take !chained into account Oleg Nesterov
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