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kprobes: Search non-suffixed symbol in blacklist

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Newer GCC versions can generate some different instances of a function
with suffixed symbols if the function is optimized and only
has a part of that. (e.g. .constprop, .part etc.)

In this case, it is not enough to check the entry of kprobe
blacklist because it only records non-suffixed symbol address.

To fix this issue, search non-suffixed symbol in blacklist if
given address is within a symbol which has a suffix.

Note that this can cause false positive cases if a kprobe-safe
function is optimized to suffixed instance and has same name
symbol which is blacklisted.
But I would like to chose a fail-safe design for this issue.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrea Righi <righi.andrea@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/154998799234.31052.6136378903570418008.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Masami Hiramatsu 2019-02-13 01:13:12 +09:00 committed by Ingo Molnar
parent 0eae81dc9f
commit 6143c6fb1e
1 changed files with 20 additions and 1 deletions
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21
kernel/kprobes.c
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@ -1396,7 +1396,7 @@ bool __weak arch_within_kprobe_blacklist(unsigned long addr)
addr < (unsigned long)__kprobes_text_end;
}
bool within_kprobe_blacklist(unsigned long addr)
static bool __within_kprobe_blacklist(unsigned long addr)
{
struct kprobe_blacklist_entry *ent;
@ -1410,7 +1410,26 @@ bool within_kprobe_blacklist(unsigned long addr)
if (addr >= ent->start_addr && addr < ent->end_addr)
return true;
}
return false;
}
bool within_kprobe_blacklist(unsigned long addr)
{
char symname[KSYM_NAME_LEN], *p;
if (__within_kprobe_blacklist(addr))
return true;
/* Check if the address is on a suffixed-symbol */
if (!lookup_symbol_name(addr, symname)) {
p = strchr(symname, '.');
if (!p)
return false;
*p = '\0';
addr = (unsigned long)kprobe_lookup_name(symname, 0);
if (addr)
return __within_kprobe_blacklist(addr);
}
return false;
}