Currently we traverse all symbols of all modules to find the specified
function for the specified module. But in reality, we just need to find
the given module and then traverse all the symbols in it.
Let's add a new parameter 'const char *modname' to function
module_kallsyms_on_each_symbol(), then we can compare the module names
directly in this function and call hook 'fn' after matching. If 'modname'
is NULL, the symbols of all modules are still traversed for compatibility
with other usage cases.
Phase1: mod1-->mod2..(subsequent modules do not need to be compared)
|
Phase2: -->f1-->f2-->f3
Assuming that there are m modules, each module has n symbols on average,
then the time complexity is reduced from O(m * n) to O(m) + O(n).
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20230116101009.23694-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Making module_kallsyms_on_each_symbol generally available, so it
can be used outside CONFIG_LIVEPATCH option in following changes.
Rather than adding another ifdef option let's make the function
generally available (when CONFIG_KALLSYMS and CONFIG_MODULES
options are defined).
Cc: Christoph Hellwig <hch@lst.de>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
module_kallsyms_lookup_name() has several exit conditions but
can't return immediately due to preempt_disable().
Refactor module_kallsyms_lookup_name() to allow returning from
anywhere, and reduce depth.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Checkpatch reports following errors:
ERROR: do not use assignment in if condition
+ if ((colon = strnchr(name, MODULE_NAME_LEN, ':')) != NULL) {
ERROR: do not use assignment in if condition
+ if ((mod = find_module_all(name, colon - name, false)) != NULL)
ERROR: do not use assignment in if condition
+ if ((ret = find_kallsyms_symbol_value(mod, name)) != 0)
ERROR: do not initialise globals to 0
+int modules_disabled = 0;
Fix them.
The following one has to remain, because the condition has to be evaluated
multiple times by the macro wait_event_interruptible_timeout().
ERROR: do not use assignment in if condition
+ if (wait_event_interruptible_timeout(module_wq,
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The commit 08126db5ff ("module: kallsyms: Fix suspicious rcu usage")
under PREEMPT_RT=y, disabling preemption introduced an unbounded
latency since the loop is not fixed. This change caused a regression
since previously preemption was not disabled and we would dereference
RCU-protected pointers explicitly. That being said, these pointers
cannot change.
Before kallsyms-specific data is prepared/or set-up, we ensure that
the unformed module is known to be unique i.e. does not already exist
(see load_module()). Therefore, we can fix this by using the common and
more appropriate RCU flavour as this section of code can be safely
preempted.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Fixes: 08126db5ff ("module: kallsyms: Fix suspicious rcu usage")
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The commit 91fb02f315 ("module: Move kallsyms support into a separate
file") changed from using strlcpy() to using strscpy() which created a
buffer overflow. That happened because:
1) an incorrect value was passed as the buffer length
2) strscpy() (unlike strlcpy()) may copy beyond the length of the
input string when copying word-by-word.
The assumption was that because it was already known that the strings
being copied would fit in the space available, it was not necessary
to correctly set the buffer length. strscpy() breaks that assumption
because although it will not touch bytes beyond the given buffer length
it may write bytes beyond the input string length when writing
word-by-word.
The result of the buffer overflow is to corrupt the symbol type
information that follows. e.g.
$ sudo cat -v /proc/kallsyms | grep '\^' | head
ffffffffc0615000 ^@ rfcomm_session_get [rfcomm]
ffffffffc061c060 ^@ session_list [rfcomm]
ffffffffc06150d0 ^@ rfcomm_send_frame [rfcomm]
ffffffffc0615130 ^@ rfcomm_make_uih [rfcomm]
ffffffffc07ed58d ^@ bnep_exit [bnep]
ffffffffc07ec000 ^@ bnep_rx_control [bnep]
ffffffffc07ec1a0 ^@ bnep_session [bnep]
ffffffffc07e7000 ^@ input_leds_event [input_leds]
ffffffffc07e9000 ^@ input_leds_handler [input_leds]
ffffffffc07e7010 ^@ input_leds_disconnect [input_leds]
Notably, the null bytes (represented above by ^@) can confuse tools.
Fix by correcting the buffer length.
Fixes: 91fb02f315 ("module: Move kallsyms support into a separate file")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
In order to allow separation of data from text, add another layout,
called data_layout. For architectures requesting separation of text
and data, only text will go in core_layout and data will go in
data_layout.
For architectures which keep text and data together, make data_layout
an alias of core_layout, that way data_layout can be used for all
data manipulations, regardless of whether data is in core_layout or
data_layout.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
debug_align() was added by commit 84e1c6bb38 ("x86: Add RO/NX
protection for loadable kernel modules")
At that time the config item was CONFIG_DEBUG_SET_MODULE_RONX.
But nowadays it has changed to CONFIG_STRICT_MODULE_RWX and
debug_align() is confusing because it has nothing to do with
DEBUG.
Rename it strict_align()
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
No functional change.
The purpose of this patch is to address the various Sparse warnings
due to the incorrect dereference/or access of an __rcu pointer.
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
No functional change.
This patch migrates kallsyms code out of core module
code kernel/module/kallsyms.c
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Zhen Lei