[for-next][PATCH 0/3] tracing: More updates for 5.16

[for-next][PATCH 0/3] tracing: More updates for 5.16

[Steven Rostedt]

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
for-next

Head SHA1: e531e90b5ab0f7ce5ff298e165214c1aec6ed187


Robin H. Johnson (2):
      tracing: Show size of requested perf buffer
      tracing: Increase PERF_MAX_TRACE_SIZE to handle Sentinel1 and docker together

Steven Rostedt (VMware) (1):
      bootconfig: Initialize ret in xbc_parse_tree()

----
 include/linux/trace_events.h    | 2 +-
 kernel/trace/trace_event_perf.c | 3 ++-
 lib/bootconfig.c                | 2 +-
 3 files changed, 4 insertions(+), 3 deletions(-)

[for-next][PATCH 1/3] bootconfig: Initialize ret in xbc_parse_tree()

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The do while loop continues while ret is zero, but ret is never
initialized. The check for ret in the loop at the while should always be
initialized, but if an empty string were to be passed in, q would be NULL
and p would be '\0', and it would break out of the loop without ever
setting ret.

Set ret to zero, and then xbc_verify_tree() would be called and catch that
it is an empty tree and report the proper error.

Link: https://lkml.kernel.org/r/20211027105753.6ab9da5f@gandalf.local.home

Fixes: bdac5c2b243f ("bootconfig: Allocate xbc_data inside xbc_init()")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 lib/bootconfig.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/bootconfig.c b/lib/bootconfig.c
index a10ab25f6fcc..70e0d52ffd24 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -836,7 +836,7 @@ static int __init xbc_verify_tree(void)
 static int __init xbc_parse_tree(void)
 {
 	char *p, *q;
-	int ret, c;
+	int ret = 0, c;
 
 	last_parent = NULL;
 	p = xbc_data;
-- 
2.33.0

[for-next][PATCH 2/3] tracing: Show size of requested perf buffer

[Steven Rostedt]

From: "Robin H. Johnson" <robbat2@gentoo.org>

If the perf buffer isn't large enough, provide a hint about how large it
needs to be for whatever is running.

Link: https://lkml.kernel.org/r/20210831043723.13481-1-robbat2@gentoo.org

Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_event_perf.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index fba8cb77a73a..a114549720d6 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -400,7 +400,8 @@ void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp)
 	BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long));
 
 	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-		      "perf buffer not large enough"))
+		      "perf buffer not large enough, wanted %d, have %d",
+		      size, PERF_MAX_TRACE_SIZE))
 		return NULL;
 
 	*rctxp = rctx = perf_swevent_get_recursion_context();
-- 
2.33.0

[for-next][PATCH 3/3] tracing: Increase PERF_MAX_TRACE_SIZE to handle Sentinel1 and docker together

[Steven Rostedt]

From: "Robin H. Johnson" <robbat2@gentoo.org>

Running endpoint security solutions like Sentinel1 that use perf-based
tracing heavily lead to this repeated dump complaining about dockerd.
The default value of 2048 is nowhere near not large enough.

Using the prior patch "tracing: show size of requested buffer", we get
"perf buffer not large enough, wanted 6644, have 6144", after repeated
up-sizing (I did 2/4/6/8K). With 8K, the problem doesn't occur at all,
so below is the trace for 6K.

I'm wondering if this value should be selectable at boot time, but this
is a good starting point.

```
------------[ cut here ]------------
perf buffer not large enough, wanted 6644, have 6144
WARNING: CPU: 1 PID: 4997 at kernel/trace/trace_event_perf.c:402 perf_trace_buf_alloc+0x8c/0xa0
Modules linked in: [..]
CPU: 1 PID: 4997 Comm: sh Tainted: G                T 5.13.13-x86_64-00039-gb3959163488e #63
Hardware name: LENOVO 20KH002JUS/20KH002JUS, BIOS N23ET66W (1.41 ) 09/02/2019
RIP: 0010:perf_trace_buf_alloc+0x8c/0xa0
Code: 80 3d 43 97 d0 01 00 74 07 31 c0 5b 5d 41 5c c3 ba 00 18 00 00 89 ee 48 c7 c7 00 82 7d 91 c6 05 25 97 d0 01 01 e8 22 ee bc 00 <0f> 0b 31 c0 eb db 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 55 89
RSP: 0018:ffffb922026b7d58 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff9da5ee012000 RCX: 0000000000000027
RDX: ffff9da881657828 RSI: 0000000000000001 RDI: ffff9da881657820
RBP: 00000000000019f4 R08: 0000000000000000 R09: ffffb922026b7b80
R10: ffffb922026b7b78 R11: ffffffff91dda688 R12: 000000000000000f
R13: ffff9da5ee012108 R14: ffff9da8816570a0 R15: ffffb922026b7e30
FS:  00007f420db1a080(0000) GS:ffff9da881640000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000060 CR3: 00000002504a8006 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 kprobe_perf_func+0x11e/0x270
 ? do_execveat_common.isra.0+0x1/0x1c0
 ? do_execveat_common.isra.0+0x5/0x1c0
 kprobe_ftrace_handler+0x10e/0x1d0
 0xffffffffc03aa0c8
 ? do_execveat_common.isra.0+0x1/0x1c0
 do_execveat_common.isra.0+0x5/0x1c0
 __x64_sys_execve+0x33/0x40
 do_syscall_64+0x6b/0xc0
 ? do_syscall_64+0x11/0xc0
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f420dc1db37
Code: ff ff 76 e7 f7 d8 64 41 89 00 eb df 0f 1f 80 00 00 00 00 f7 d8 64 41 89 00 eb dc 0f 1f 84 00 00 00 00 00 b8 3b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 01 43 0f 00 f7 d8 64 89 01 48
RSP: 002b:00007ffd4e8b4e38 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f420dc1db37
RDX: 0000564338d1e740 RSI: 0000564338d32d50 RDI: 0000564338d28f00
RBP: 0000564338d28f00 R08: 0000564338d32d50 R09: 0000000000000020
R10: 00000000000001b6 R11: 0000000000000246 R12: 0000564338d28f00
R13: 0000564338d32d50 R14: 0000564338d1e740 R15: 0000564338d28c60
---[ end trace 83ab3e8e16275e49 ]---
```

Link: https://lkml.kernel.org/r/20210831043723.13481-2-robbat2@gentoo.org

Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/trace_events.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 3e475eeb5a99..50453b287615 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -671,7 +671,7 @@ struct trace_event_file {
 	}								\
 	early_initcall(trace_init_perf_perm_##name);
 
-#define PERF_MAX_TRACE_SIZE	2048
+#define PERF_MAX_TRACE_SIZE	8192
 
 #define MAX_FILTER_STR_VAL	256	/* Should handle KSYM_SYMBOL_LEN */
 
-- 
2.33.0