linux-stable.git/kernel, branch v4.9.203

printk: Give error on attempt to set log buffer length to over 2G

2019-11-25T08:53:45+00:00

[ Upstream commit e6fe3e5b7d16e8f146a4ae7fe481bc6e97acde1e ]

The current printk() is ready to handle log buffer size up to 2G.
Give an explicit error for users who want to use larger log buffer.

Also fix printk formatting to show the 2G as a positive number.

Link: http://lkml.kernel.org/r/20181008135916.gg4kkmoki5bgtco5@pathway.suse.cz
Cc: rostedt@goodmis.org
Cc: linux-kernel@vger.kernel.org
Suggested-by: Sergey Senozhatsky 
Signed-off-by: He Zhe 
Reviewed-by: Sergey Senozhatsky 
[pmladek: Fixed to the really safe limit 2GB.]
Signed-off-by: Petr Mladek 
Signed-off-by: Sasha Levin

cpu/SMT: State SMT is disabled even with nosmt and without "=force"

2019-11-25T08:53:32+00:00

[ Upstream commit d0e7d14455d41163126afecd0fcce935463cc512 ]

When booting with "nosmt=force" a message is issued into dmesg to
confirm that SMT has been force-disabled but such a message is not
issued when only "nosmt" is on the kernel command line.

Fix that.

Signed-off-by: Borislav Petkov 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20181004172227.10094-1-bp@alien8.de
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

kprobes: Don't call BUG_ON() if there is a kprobe in use on free list

2019-11-25T08:52:15+00:00

[ Upstream commit cbdd96f5586151e48317d90a403941ec23f12660 ]

Instead of calling BUG_ON(), if we find a kprobe in use on free kprobe
list, just remove it from the list and keep it on kprobe hash list
as same as other in-use kprobes.

Signed-off-by: Masami Hiramatsu 
Cc: Anil S Keshavamurthy 
Cc: David S . Miller 
Cc: Linus Torvalds 
Cc: Naveen N . Rao 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/153666126882.21306.10738207224288507996.stgit@devbox
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

signal: Properly deliver SIGILL from uprobes

2019-11-25T08:52:12+00:00

[ Upstream commit 55a3235fc71bf34303e34a95eeee235b2d2a35dd ]

For userspace to tell the difference between a random signal and an
exception, the exception must include siginfo information.

Using SEND_SIG_FORCED for SIGILL is thus wrong, and it will result
in userspace seeing si_code == SI_USER (like a random signal) instead
of si_code == SI_KERNEL or a more specific si_code as all exceptions
deliver.

Therefore replace force_sig_info(SIGILL, SEND_SIG_FORCE, current)
with force_sig(SIG_ILL, current) which gets this right and is
shorter and easier to type.

Fixes: 014940bad8e4 ("uprobes/x86: Send SIGILL if arch_uprobe_post_xol() fails")
Fixes: 0b5256c7f173 ("uprobes: Send SIGILL if handle_trampoline() fails")
Reviewed-by: Thomas Gleixner 
Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Sasha Levin

signal: Always ignore SIGKILL and SIGSTOP sent to the global init

2019-11-25T08:52:12+00:00

[ Upstream commit 86989c41b5ea08776c450cb759592532314a4ed6 ]

If the first process started (aka /sbin/init) receives a SIGKILL it
will panic the system if it is delivered.  Making the system unusable
and undebugable.  It isn't much better if the first process started
receives SIGSTOP.

So always ignore SIGSTOP and SIGKILL sent to init.

This is done in a separate clause in sig_task_ignored as force_sig_info
can clear SIG_UNKILLABLE and this protection should work even then.

Reviewed-by: Thomas Gleixner 
Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Sasha Levin

cpu/speculation: Uninline and export CPU mitigations helpers

2019-11-16T09:29:54+00:00

commit 731dc9df975a5da21237a18c3384f811a7a41cc6 upstream.

A kernel module may need to check the value of the "mitigations=" kernel
command line parameter as part of its setup when the module needs
to perform software mitigations for a CPU flaw.

Uninline and export the helper functions surrounding the cpu_mitigations
enum to allow for their usage from a module.

Lastly, privatize the enum and cpu_mitigations variable since the value of
cpu_mitigations can be checked with the exported helper functions.

Signed-off-by: Tyler Hicks 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

alarmtimer: Change remaining ENOTSUPP to EOPNOTSUPP

2019-11-10T10:23:32+00:00

Fix backport of commit f18ddc13af981ce3c7b7f26925f099e7c6929aba upstream.

Update backport to change ENOTSUPP to EOPNOTSUPP in
alarm_timer_{del,set}(), which were removed in
f2c45807d3992fe0f173f34af9c347d907c31686 in v4.13-rc1.

Fixes: 65b7a5a36afb11a6769a70308c1ef3a2afae6bf4

Signed-off-by: Petr Vorel 
Acked-by: Thadeu Lima de Souza Cascardo 
Signed-off-by: Greg Kroah-Hartman

tracing: Initialize iter->seq after zeroing in tracing_read_pipe()

2019-11-06T11:18:13+00:00

[ Upstream commit d303de1fcf344ff7c15ed64c3f48a991c9958775 ]

A customer reported the following softlockup:

[899688.160002] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [test.sh:16464]
[899688.160002] CPU: 0 PID: 16464 Comm: test.sh Not tainted 4.12.14-6.23-azure #1 SLE12-SP4
[899688.160002] RIP: 0010:up_write+0x1a/0x30
[899688.160002] Kernel panic - not syncing: softlockup: hung tasks
[899688.160002] RIP: 0010:up_write+0x1a/0x30
[899688.160002] RSP: 0018:ffffa86784d4fde8 EFLAGS: 00000257 ORIG_RAX: ffffffffffffff12
[899688.160002] RAX: ffffffff970fea00 RBX: 0000000000000001 RCX: 0000000000000000
[899688.160002] RDX: ffffffff00000001 RSI: 0000000000000080 RDI: ffffffff970fea00
[899688.160002] RBP: ffffffffffffffff R08: ffffffffffffffff R09: 0000000000000000
[899688.160002] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8b59014720d8
[899688.160002] R13: ffff8b59014720c0 R14: ffff8b5901471090 R15: ffff8b5901470000
[899688.160002]  tracing_read_pipe+0x336/0x3c0
[899688.160002]  __vfs_read+0x26/0x140
[899688.160002]  vfs_read+0x87/0x130
[899688.160002]  SyS_read+0x42/0x90
[899688.160002]  do_syscall_64+0x74/0x160

It caught the process in the middle of trace_access_unlock(). There is
no loop. So, it must be looping in the caller tracing_read_pipe()
via the "waitagain" label.

Crashdump analyze uncovered that iter->seq was completely zeroed
at this point, including iter->seq.seq.size. It means that
print_trace_line() was never able to print anything and
there was no forward progress.

The culprit seems to be in the code:

	/* reset all but tr, trace, and overruns */
	memset(&iter->seq, 0,
	       sizeof(struct trace_iterator) -
	       offsetof(struct trace_iterator, seq));

It was added by the commit 53d0aa773053ab182877 ("ftrace:
add logic to record overruns"). It was v2.6.27-rc1.
It was the time when iter->seq looked like:

     struct trace_seq {
	unsigned char		buffer[PAGE_SIZE];
	unsigned int		len;
     };

There was no "size" variable and zeroing was perfectly fine.

The solution is to reinitialize the structure after or without
zeroing.

Link: http://lkml.kernel.org/r/20191011142134.11997-1-pmladek@suse.com

Signed-off-by: Petr Mladek 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Sasha Levin

tracing: Get trace_array reference for available_tracers files

2019-10-17T20:42:46+00:00

commit 194c2c74f5532e62c218adeb8e2b683119503907 upstream.

As instances may have different tracers available, we need to look at the
trace_array descriptor that shows the list of the available tracers for the
instance. But there's a race between opening the file and an admin
deleting the instance. The trace_array_get() needs to be called before
accessing the trace_array.

Cc: stable@vger.kernel.org
Fixes: 607e2ea167e56 ("tracing: Set up infrastructure to allow tracers for instances")
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing/hwlat: Don't ignore outer-loop duration when calculating max_latency

2019-10-17T20:42:46+00:00

commit fc64e4ad80d4b72efce116f87b3174f0b7196f8e upstream.

max_latency is intended to record the maximum ever observed hardware
latency, which may occur in either part of the loop (inner/outer). So
we need to also consider the outer-loop sample when updating
max_latency.

Link: http://lkml.kernel.org/r/157073345463.17189.18124025522664682811.stgit@srivatsa-ubuntu

Fixes: e7c15cd8a113 ("tracing: Added hardware latency tracer")
Cc: stable@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat (VMware) 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman