From: Michael Petlan <mpetlan@xxxxxxxxxx>
commit 3cf6a32f3f2a45944dd5be5c6ac4deb46bcd3bee upstream.
Before this patch, the symbol end address fixup to be called, needed two
conditions being met:
if (prev->end == prev->start && prev->end != curr->start)
Where
"prev->end == prev->start" means that prev is zero-long
(and thus needs a fixup)
and
"prev->end != curr->start" means that fixup hasn't been applied yet
However, this logic is incorrect in the following situation:
*curr = {rb_node = {__rb_parent_color = 278218928,
rb_right = 0x0, rb_left = 0x0},
start = 0xc000000000062354,
end = 0xc000000000062354, namelen = 40, type = 2 '\002',
binding = 0 '\000', idle = 0 '\000', ignore = 0 '\000',
inlined = 0 '\000', arch_sym = 0 '\000', annotate2 = false,
name = 0x1159739e "kprobe_optinsn_page\t[__builtin__kprobes]"}
*prev = {rb_node = {__rb_parent_color = 278219041,
rb_right = 0x109548b0, rb_left = 0x109547c0},
start = 0xc000000000062354,
end = 0xc000000000062354, namelen = 12, type = 2 '\002',
binding = 1 '\001', idle = 0 '\000', ignore = 0 '\000',
inlined = 0 '\000', arch_sym = 0 '\000', annotate2 = false,
name = 0x1095486e "optinsn_slot"}
In this case, prev->start == prev->end == curr->start == curr->end,
thus the condition above thinks that "we need a fixup due to zero
length of prev symbol, but it has been probably done, since the
prev->end == curr->start", which is wrong.
After the patch, the execution path proceeds to arch__symbols__fixup_end
function which fixes up the size of prev symbol by adding page_size to
its end offset.
Fixes: 3b01a413c196c910 ("perf symbols: Improve kallsyms symbol end addr calculation")
Signed-off-by: Michael Petlan <mpetlan@xxxxxxxxxx>
Cc: Athira Jajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kajol Jain <kjain@xxxxxxxxxxxxx>
Cc: Madhavan Srinivasan <maddy@xxxxxxxxxxxxx>
Link: http://lore.kernel.org/lkml/20220317135536.805-1-mpetlan@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/perf/util/symbol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -231,7 +231,7 @@ void symbols__fixup_end(struct rb_root_c
prev = curr;
curr = rb_entry(nd, struct symbol, rb_node);
- if (prev->end == prev->start && prev->end != curr->start)
+ if (prev->end == prev->start || prev->end != curr->start)
arch__symbols__fixup_end(prev, curr);
}
