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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Waiman Long <longman@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	the arch/x86 maintainers <x86@kernel.org>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	huang ying <huang.ying.caritas@gmail.com>,
	Roman Gushchin <guro@fb.com>, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	"Steven Rostedt (VMware)" <rostedt@goodmis.org>
Subject: [PATCH 4.9 05/41] trace: Fix preempt_enable_no_resched() abuse
Date: Tue, 30 Apr 2019 13:38:16 +0200	[thread overview]
Message-ID: <20190430113525.540918012@linuxfoundation.org> (raw)
In-Reply-To: <20190430113524.451237916@linuxfoundation.org>

From: Peter Zijlstra <peterz@infradead.org>

commit d6097c9e4454adf1f8f2c9547c2fa6060d55d952 upstream.

Unless the very next line is schedule(), or implies it, one must not use
preempt_enable_no_resched(). It can cause a preemption to go missing and
thereby cause arbitrary delays, breaking the PREEMPT=y invariant.

Link: http://lkml.kernel.org/r/20190423200318.GY14281@hirez.programming.kicks-ass.net

Cc: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: the arch/x86 maintainers <x86@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: huang ying <huang.ying.caritas@gmail.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: stable@vger.kernel.org
Fixes: 2c2d7329d8af ("tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp()")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/trace/ring_buffer.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -701,7 +701,7 @@ u64 ring_buffer_time_stamp(struct ring_b
 
 	preempt_disable_notrace();
 	time = rb_time_stamp(buffer);
-	preempt_enable_no_resched_notrace();
+	preempt_enable_notrace();
 
 	return time;
 }



  parent reply	other threads:[~2019-04-30 11:40 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-30 11:38 [PATCH 4.9 00/41] 4.9.172-stable review Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 01/41] kbuild: simplify ld-option implementation Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 02/41] cifs: do not attempt cifs operation on smb2+ rename error Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 03/41] tracing: Fix a memory leak by early error exit in trace_pid_write() Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 04/41] MIPS: scall64-o32: Fix indirect syscall number load Greg Kroah-Hartman
2019-04-30 11:38 ` Greg Kroah-Hartman [this message]
2019-04-30 11:38 ` [PATCH 4.9 06/41] IB/rdmavt: Fix frwr memory registration Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 07/41] sched/numa: Fix a possible divide-by-zero Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 08/41] ceph: ensure d_name stability in ceph_dentry_hash() Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 09/41] ceph: fix ci->i_head_snapc leak Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 10/41] nfsd: Dont release the callback slot unless it was actually held Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 11/41] sunrpc: dont mark uninitialised items as VALID Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 12/41] Input: synaptics-rmi4 - write config register values to the right offset Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 13/41] dmaengine: sh: rcar-dmac: With cyclic DMA residue 0 is valid Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 14/41] ARM: 8857/1: efi: enable CP15 DMB instructions before cleaning the cache Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 15/41] drm/vc4: Fix memory leak during gpu reset Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 16/41] drm/vc4: Fix compilation error reported by kbuild test bot Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 17/41] USB: Add new USB LPM helpers Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 18/41] USB: Consolidate LPM checks to avoid enabling LPM twice Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 19/41] vsock/virtio: fix kernel panic from virtio_transport_reset_no_sock Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 20/41] tipc: handle the err returned from cmd header function Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 21/41] slip: make slhc_free() silently accept an error pointer Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 22/41] intel_th: gth: Fix an off-by-one in output unassigning Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 23/41] fs/proc/proc_sysctl.c: Fix a NULL pointer dereference Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 24/41] NFS: Forbid setting AF_INET6 to "struct sockaddr_in"->sin_family Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 25/41] netfilter: ebtables: CONFIG_COMPAT: drop a bogus WARN_ON Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 26/41] fm10k: Fix a potential NULL pointer dereference Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 27/41] tipc: check bearer name with right length in tipc_nl_compat_bearer_enable Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 28/41] tipc: check link name with right length in tipc_nl_compat_link_set Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 29/41] Revert "block/loop: Use global lock for ioctl() operation." Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 30/41] ipv4: add sanity checks in ipv4_link_failure() Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 31/41] mlxsw: spectrum: Fix autoneg status in ethtool Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 32/41] net/mlx5e: ethtool, Remove unsupported SFP EEPROM high pages query Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 33/41] net: rds: exchange of 8K and 1M pool Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 34/41] team: fix possible recursive locking when add slaves Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 35/41] net: stmmac: move stmmac_check_ether_addr() to driver probe Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 36/41] ipv4: set the tcp_min_rtt_wlen range from 0 to one day Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 37/41] ipv6: frags: fix a lockdep false positive Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 38/41] net: IP defrag: encapsulate rbtree defrag code into callable functions Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 39/41] ipv6: remove dependency of nf_defrag_ipv6 on ipv6 module Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 40/41] net: IP6 defrag: use rbtrees for IPv6 defrag Greg Kroah-Hartman
2019-04-30 11:38 ` [PATCH 4.9 41/41] net: IP6 defrag: use rbtrees in nf_conntrack_reasm.c Greg Kroah-Hartman
2019-04-30 22:26 ` [PATCH 4.9 00/41] 4.9.172-stable review kernelci.org bot
2019-04-30 22:30 ` shuah
2019-05-01  6:01 ` Naresh Kamboju
2019-05-01  8:24 ` Jon Hunter
2019-05-01  8:24   ` Jon Hunter
2019-05-01 16:43 ` Guenter Roeck

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