diff options
| author | Steven Rostedt <rostedt@goodmis.org> | 2025-02-25 13:20:06 -0500 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2025-02-25 13:25:13 -0500 |
| commit | da0f622b344be769ed61e7c1caf95cd0cdb47964 (patch) | |
| tree | 01d370fe9cb88124059355a7f38bf5bccb864ed2 | |
| parent | 6eeca746fa5f1dd03c6ee05cb03f5eb1ddda1c81 (diff) | |
ftrace: Check against is_kernel_text() instead of kaslr_offset()
As kaslr_offset() is architecture dependent and also may not be defined by
all architectures, when zeroing out unused weak functions, do not check
against kaslr_offset(), but instead check if the address is within the
kernel text sections. If KASLR added a shift to the zeroed out function,
it would still not be located in the kernel text. This is a more robust
way to test if the text is valid or not.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: "Arnd Bergmann" <arnd@arndb.de>
Link: https://lore.kernel.org/20250225182054.471759017@goodmis.org
Fixes: ef378c3b8233 ("scripts/sorttable: Zero out weak functions in mcount_loc table")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Reported-by: Mark Brown <broonie@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/all/20250224180805.GA1536711@ax162/
Closes: https://lore.kernel.org/all/5225b07b-a9b2-4558-9d5f-aa60b19f6317@sirena.org.uk/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
| -rw-r--r-- | kernel/trace/ftrace.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 183f72cf15ed..bec7b5dbdb3b 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -7004,7 +7004,6 @@ static int ftrace_process_locs(struct module *mod, unsigned long count; unsigned long *p; unsigned long addr; - unsigned long kaslr; unsigned long flags = 0; /* Shut up gcc */ unsigned long pages; int ret = -ENOMEM; @@ -7056,9 +7055,6 @@ static int ftrace_process_locs(struct module *mod, ftrace_pages->next = start_pg; } - /* For zeroed locations that were shifted for core kernel */ - kaslr = !mod ? kaslr_offset() : 0; - p = start; pg = start_pg; while (p < end) { @@ -7072,7 +7068,18 @@ static int ftrace_process_locs(struct module *mod, * object files to satisfy alignments. * Skip any NULL pointers. */ - if (!addr || addr == kaslr) { + if (!addr) { + skipped++; + continue; + } + + /* + * If this is core kernel, make sure the address is in core + * or inittext, as weak functions get zeroed and KASLR can + * move them to something other than zero. It just will not + * move it to an area where kernel text is. + */ + if (!mod && !(is_kernel_text(addr) || is_kernel_inittext(addr))) { skipped++; continue; } |