From: Oleg Nesterov <oleg@redhat.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
Pratyush Anand <panand@redhat.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH v3 14/14] uprobes: fix the waitqueue_active() check in xol_free_insn_slot()
Date: Tue, 21 Jul 2015 15:40:36 +0200 [thread overview]
Message-ID: <20150721134036.GA4799@redhat.com> (raw)
In-Reply-To: <20150721133945.GA4718@redhat.com>
The xol_free_insn_slot()->waitqueue_active() check is buggy. We need
mb() after we set the conditon for wait_event(), or xol_take_insn_slot()
can miss the wakeup.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/events/uprobes.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 2d5b7bd..4e5e979 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1337,6 +1337,7 @@ static void xol_free_insn_slot(struct task_struct *tsk)
clear_bit(slot_nr, area->bitmap);
atomic_dec(&area->slot_count);
+ smp_mb__after_atomic(); /* pairs with prepare_to_wait() */
if (waitqueue_active(&area->wq))
wake_up(&area->wq);
--
1.5.5.1
next prev parent reply other threads:[~2015-07-21 13:42 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-21 13:39 [PATCH v3 00/14] uprobes: longjmp / special-mapping fixes Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 01/14] uprobes: Introduce get_uprobe() Oleg Nesterov
2015-07-31 13:57 ` [tip:perf/core] " tip-bot for Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 02/14] uprobes: Introduce free_ret_instance() Oleg Nesterov
2015-07-31 13:58 ` [tip:perf/core] " tip-bot for Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 03/14] uprobes: Send SIGILL if handle_trampoline() fails Oleg Nesterov
2015-07-31 13:58 ` [tip:perf/core] " tip-bot for Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 04/14] uprobes: Change prepare_uretprobe() to use uprobe_warn() Oleg Nesterov
2015-07-31 13:58 ` [tip:perf/core] " tip-bot for Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 05/14] uprobes: Change handle_trampoline() to find the next chain beforehand Oleg Nesterov
2015-07-31 13:59 ` [tip:perf/core] " tip-bot for Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 06/14] uprobes: Export struct return_instance, introduce arch_uretprobe_is_alive() Oleg Nesterov
2015-07-31 13:59 ` [tip:perf/core] uprobes: Export 'struct return_instance', " tip-bot for Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 07/14] uprobes/x86: Reimplement arch_uretprobe_is_alive() Oleg Nesterov
2015-07-31 13:59 ` [tip:perf/core] uprobes/x86: Reimplement arch_uretprobe_is_alive( ) tip-bot for Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 08/14] uprobes: Change handle_trampoline() to flush the frames invalidated by longjmp() Oleg Nesterov
2015-07-31 14:00 ` [tip:perf/core] " tip-bot for Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 09/14] uprobes: Change prepare_uretprobe() to (try to) flush the dead frames Oleg Nesterov
2015-07-31 14:00 ` [tip:perf/core] " tip-bot for Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 10/14] uprobes: Add the "enum rp_check ctx" arg to arch_uretprobe_is_alive() Oleg Nesterov
2015-07-31 14:00 ` [tip:perf/core] " tip-bot for Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 11/14] uprobes/x86: Make arch_uretprobe_is_alive(RP_CHECK_CALL) more clever Oleg Nesterov
2015-07-31 14:01 ` [tip:perf/core] uprobes/x86: Make arch_uretprobe_is_alive( RP_CHECK_CALL) " tip-bot for Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 12/14] uprobes: fix the usage of install_special_mapping() Oleg Nesterov
2015-07-31 14:01 ` [tip:perf/core] uprobes: Fix the usage of install_special_mapping () tip-bot for Oleg Nesterov
2015-07-21 13:40 ` [PATCH v3 13/14] uprobes: use vm_special_mapping to name the xol vma Oleg Nesterov
2015-07-31 14:01 ` [tip:perf/core] uprobes: Use vm_special_mapping to name the XOL vma tip-bot for Oleg Nesterov
2015-07-21 13:40 ` Oleg Nesterov [this message]
2015-07-31 14:02 ` [tip:perf/core] uprobes: Fix the waitqueue_active() check in xol_free_insn_slot() tip-bot for Oleg Nesterov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150721134036.GA4799@redhat.com \
--to=oleg@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=mingo@kernel.org \
--cc=panand@redhat.com \
--cc=srikar@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).