22 Sep, 2020
1 commit
-
Drop repeated words in kernel/trace/.
{and, the, not}Link: https://lkml.kernel.org/r/20200807033259.13778-1-rdunlap@infradead.org
Cc: Ingo Molnar
Signed-off-by: Randy Dunlap
Signed-off-by: Steven Rostedt (VMware)
23 Apr, 2020
1 commit
-
Fix the following sparse warning:
kernel/trace/tracing_map.c:286:6: warning: symbol
'tracing_map_array_clear' was not declared. Should it be static?
kernel/trace/tracing_map.c:297:6: warning: symbol
'tracing_map_array_free' was not declared. Should it be static?
kernel/trace/tracing_map.c:319:26: warning: symbol
'tracing_map_array_alloc' was not declared. Should it be static?Link: http://lkml.kernel.org/r/20200410073312.38855-1-yanaijie@huawei.com
Reported-by: Hulk Robot
Signed-off-by: Jason Yan
Signed-off-by: Steven Rostedt (VMware)
20 Dec, 2019
1 commit
-
The compare functions of the histogram code would be specific for the size
of the value being compared (byte, short, int, long long). It would
reference the value from the array via the type of the compare, but the
value was stored in a 64 bit number. This is fine for little endian
machines, but for big endian machines, it would end up comparing zeros or
all ones (depending on the sign) for anything but 64 bit numbers.To fix this, first derference the value as a u64 then convert it to the type
being compared.Link: http://lkml.kernel.org/r/20191211103557.7bed6928@gandalf.local.home
Cc: stable@vger.kernel.org
Fixes: 08d43a5fa063e ("tracing: Add lock-free tracing_map")
Acked-by: Tom Zanussi
Reported-by: Sven Schnelle
Signed-off-by: Steven Rostedt (VMware)
17 Aug, 2018
1 commit
-
Add the SPDX License header to ease license compliance management.
Signed-off-by: Steven Rostedt (VMware)
13 Jun, 2018
1 commit
-
The vmalloc() function has no 2-factor argument form, so multiplication
factors need to be wrapped in array_size(). This patch replaces cases of:vmalloc(a * b)
with:
vmalloc(array_size(a, b))as well as handling cases of:
vmalloc(a * b * c)
with:
vmalloc(array3_size(a, b, c))
This does, however, attempt to ignore constant size factors like:
vmalloc(4 * 1024)
though any constants defined via macros get caught up in the conversion.
Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.The Coccinelle script used for this was:
// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@(
vmalloc(
- (sizeof(TYPE)) * E
+ sizeof(TYPE) * E
, ...)
|
vmalloc(
- (sizeof(THING)) * E
+ sizeof(THING) * E
, ...)
)// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@(
vmalloc(
- sizeof(u8) * (COUNT)
+ COUNT
, ...)
|
vmalloc(
- sizeof(__u8) * (COUNT)
+ COUNT
, ...)
|
vmalloc(
- sizeof(char) * (COUNT)
+ COUNT
, ...)
|
vmalloc(
- sizeof(unsigned char) * (COUNT)
+ COUNT
, ...)
|
vmalloc(
- sizeof(u8) * COUNT
+ COUNT
, ...)
|
vmalloc(
- sizeof(__u8) * COUNT
+ COUNT
, ...)
|
vmalloc(
- sizeof(char) * COUNT
+ COUNT
, ...)
|
vmalloc(
- sizeof(unsigned char) * COUNT
+ COUNT
, ...)
)// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@(
vmalloc(
- sizeof(TYPE) * (COUNT_ID)
+ array_size(COUNT_ID, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(TYPE) * COUNT_ID
+ array_size(COUNT_ID, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(TYPE) * (COUNT_CONST)
+ array_size(COUNT_CONST, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(TYPE) * COUNT_CONST
+ array_size(COUNT_CONST, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(THING) * (COUNT_ID)
+ array_size(COUNT_ID, sizeof(THING))
, ...)
|
vmalloc(
- sizeof(THING) * COUNT_ID
+ array_size(COUNT_ID, sizeof(THING))
, ...)
|
vmalloc(
- sizeof(THING) * (COUNT_CONST)
+ array_size(COUNT_CONST, sizeof(THING))
, ...)
|
vmalloc(
- sizeof(THING) * COUNT_CONST
+ array_size(COUNT_CONST, sizeof(THING))
, ...)
)// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@vmalloc(
- SIZE * COUNT
+ array_size(COUNT, SIZE)
, ...)// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@(
vmalloc(
- sizeof(TYPE) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(TYPE) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(TYPE) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(TYPE) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
vmalloc(
- sizeof(THING) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
vmalloc(
- sizeof(THING) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
vmalloc(
- sizeof(THING) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
vmalloc(
- sizeof(THING) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
)// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@(
vmalloc(
- sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
vmalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
vmalloc(
- sizeof(THING1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
vmalloc(
- sizeof(THING1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
vmalloc(
- sizeof(TYPE1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
|
vmalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
)// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@(
vmalloc(
- (COUNT) * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- COUNT * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- COUNT * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- (COUNT) * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- COUNT * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- (COUNT) * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- (COUNT) * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vmalloc(
- COUNT * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
)// Any remaining multi-factor products, first at least 3-factor products
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@(
vmalloc(C1 * C2 * C3, ...)
|
vmalloc(
- E1 * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
)// And then all remaining 2 factors products when they're not all constants.
@@
expression E1, E2;
constant C1, C2;
@@(
vmalloc(C1 * C2, ...)
|
vmalloc(
- E1 * E2
+ array_size(E1, E2)
, ...)
)Signed-off-by: Kees Cook
11 Mar, 2018
3 commits
-
In order to allow information to be passed between trace events, add
support for per-element variables to tracing_map. This provides a
means for histograms to associate a value or values with an entry when
it's saved or updated, and retrieved by a subsequent event occurrences.Variables can be set using tracing_map_set_var() and read using
tracing_map_read_var(). tracing_map_var_set() returns true or false
depending on whether or not the variable has been set or not, which is
important for event-matching applications.tracing_map_read_var_once() reads the variable and resets it to the
'unset' state, implementing read-once variables, which are also
important for event-matching uses.Link: http://lkml.kernel.org/r/7fa001108252556f0c6dd9d63145eabfe3370d1a.1516069914.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi
Signed-off-by: Steven Rostedt (VMware) -
We now have the logic to detect and remove duplicates in the
tracing_map hash table. The code which merges duplicates in the
histogram is redundant now. So, modify this code just to detect
duplicates. The duplication detection code is still kept to ensure
that any rare race condition which might cause duplicates does not go
unnoticed.Link: http://lkml.kernel.org/r/55215cf59e2674391bdaf772fdafc4c393352b03.1516069914.git.tom.zanussi@linux.intel.com
Signed-off-by: Vedang Patel
Signed-off-by: Tom Zanussi
Signed-off-by: Steven Rostedt (VMware) -
A duplicate in the tracing_map hash table is when 2 different entries
have the same key and, as a result, the key_hash. This is possible due
to a race condition in the algorithm. This race condition is inherent to
the algorithm and not a bug. This was fine because, until now, we were
only interested in the sum of all the values related to a particular
key (the duplicates are dealt with in tracing_map_sort_entries()). But,
with the inclusion of variables[1], we are interested in individual
values. So, it will not be clear what value to choose when
there are duplicates. So, the duplicates need to be removed.The duplicates can occur in the code in the following scenarios:
- A thread is in the process of adding a new element. It has
successfully executed cmpxchg() and inserted the key. But, it is still
not done acquiring the trace_map_elt struct, populating it and storing
the pointer to the struct in the value field of tracing_map hash table.
If another thread comes in at this time and wants to add an element with
the same key, it will not see the current element and add a new one.- There are multiple threads trying to execute cmpxchg at the same time,
one of the threads will succeed and the others will fail. The ones which
fail will go ahead increment 'idx' and add a new element there creating
a duplicate.This patch detects and avoids the first condition by asking the thread
which detects the duplicate to loop one more time. There is also a
possibility of infinite loop if the thread which is trying to insert
goes to sleep indefinitely and the one which is trying to insert a new
element detects a duplicate. Which is why, the thread loops for
map_size iterations before returning NULL.The second scenario is avoided by preventing the threads which failed
cmpxchg() from incrementing idx. This way, they will loop
around and check if the thread which succeeded in executing cmpxchg()
had the same key.[1] http://lkml.kernel.org/r/cover.1498510759.git.tom.zanussi@linux.intel.com
Link: http://lkml.kernel.org/r/e178e89ec399240331d383bd5913d649713110f4.1516069914.git.tom.zanussi@linux.intel.com
Signed-off-by: Vedang Patel
Signed-off-by: Tom Zanussi
Signed-off-by: Steven Rostedt (VMware)
05 Oct, 2017
1 commit
-
Lookups inflate the hitcount, making it essentially useless. Only
inserts and updates should really affect the hitcount anyway, so
explicitly filter lookups out.Link: http://lkml.kernel.org/r/c8d9dc39d269a8abf88bf4102d0dfc65deb0fc7f.1506105045.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi
Signed-off-by: Steven Rostedt (VMware)
24 Aug, 2017
1 commit
-
kmemleak reported the below leak when I was doing clear of the hist
trigger. With this patch, the kmeamleak is gone.unreferenced object 0xffff94322b63d760 (size 32):
comm "bash", pid 1522, jiffies 4403687962 (age 2442.311s)
hex dump (first 32 bytes):
00 01 00 00 04 00 00 00 08 00 00 00 ff 00 00 00 ................
10 00 00 00 00 00 00 00 80 a8 7a f2 31 94 ff ff ..........z.1...
backtrace:
[] kmemleak_alloc+0x4a/0xa0
[] kmem_cache_alloc_trace+0xca/0x1d0
[] tracing_map_array_alloc+0x26/0x140
[] kretprobe_trampoline+0x0/0x50
[] create_hist_data+0x535/0x750
[] event_hist_trigger_func+0x1f7/0x420
[] event_trigger_write+0xfd/0x1a0
[] __vfs_write+0x37/0x170
[] vfs_write+0xb2/0x1b0
[] SyS_write+0x55/0xc0
[] do_syscall_64+0x67/0x150
[] return_from_SYSCALL_64+0x0/0x6a
[] 0xffffffffffffffff
unreferenced object 0xffff9431f27aa880 (size 128):
comm "bash", pid 1522, jiffies 4403687962 (age 2442.311s)
hex dump (first 32 bytes):
00 00 8c 2a 32 94 ff ff 00 f0 8b 2a 32 94 ff ff ...*2......*2...
00 e0 8b 2a 32 94 ff ff 00 d0 8b 2a 32 94 ff ff ...*2......*2...
backtrace:
[] kmemleak_alloc+0x4a/0xa0
[] __kmalloc+0xe8/0x220
[] tracing_map_array_alloc+0xb1/0x140
[] kretprobe_trampoline+0x0/0x50
[] create_hist_data+0x535/0x750
[] event_hist_trigger_func+0x1f7/0x420
[] event_trigger_write+0xfd/0x1a0
[] __vfs_write+0x37/0x170
[] vfs_write+0xb2/0x1b0
[] SyS_write+0x55/0xc0
[] do_syscall_64+0x67/0x150
[] return_from_SYSCALL_64+0x0/0x6a
[] 0xffffffffffffffffLink: http://lkml.kernel.org/r/1502705898-27571-1-git-send-email-chuhu@redhat.com
Cc: stable@vger.kernel.org
Fixes: 08d43a5fa063 ("tracing: Add lock-free tracing_map")
Signed-off-by: Chunyu Hu
Signed-off-by: Steven Rostedt (VMware)
26 Apr, 2016
2 commits
-
If tracing_map_elt_alloc() fails, it will return ERR_PTR() instead of
NULL, so change the check to IS_ERROR(). We also need to set the
failed entry in the map->elts array to NULL instead of ERR_PTR() so
tracing_map_free_elts() doesn't try freeing an ERR_PTR().tracing_map_free_elts() should also zero out what it frees so a
reentrant call won't find previously freed elements.Link: http://lkml.kernel.org/r/f29d03b00bce3aac8cf151a8a30e6c83e5fee66d.1461610073.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi
Signed-off-by: Steven Rostedt -
tracing_map_elt_alloc() returns ERR_PTRs on error, never NULL.
Fixes: 08d43a5fa063 ('tracing: Add lock-free tracing_map')
Link: http://lkml.kernel.org/r/20160423102347.GA11136@mwandaAcked-by: Tom Zanussi
Signed-off-by: Dan Carpenter
Signed-off-by: Steven Rostedt
20 Apr, 2016
2 commits
-
Make it clear exactly how many keys and values are supported through
better defines, and add 1 to the vals count, since normally clients
want support for at least a hitcount and two other values.Also, note the error return value for tracing_map_add_key/val_field()
in the comments.Link: http://lkml.kernel.org/r/6696fa02ebc716aa344c27a571a2afaa25e5b4d4.1457029949.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi
Signed-off-by: Steven Rostedt -
Add tracing_map, a special-purpose lock-free map for tracing.
tracing_map is designed to aggregate or 'sum' one or more values
associated with a specific object of type tracing_map_elt, which
is associated by the map to a given key.It provides various hooks allowing per-tracer customization and is
separated out into a separate file in order to allow it to be shared
between multiple tracers, but isn't meant to be generally used outside
of that context.The tracing_map implementation was inspired by lock-free map
algorithms originated by Dr. Cliff Click:http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable
http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdfLink: http://lkml.kernel.org/r/b43d68d1add33582a396f553c8ef705a33a6a748.1449767187.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi
Tested-by: Masami Hiramatsu
Reviewed-by: Namhyung Kim
Signed-off-by: Steven Rostedt