[Crash-utility] [PATCH 2/3] Enable demangling a mangled Rust support
Without the patch:
crash> bt
PID: 3520 TASK: ffff8f240f670000 CPU: 1 COMMAND: "insmod"
#0 [ffffd08c4f063a20] machine_kexec at ffffffff9575e60e
#1 [ffffd08c4f063a40] __crash_kexec at ffffffff958db711
#2 [ffffd08c4f063b00] panic at ffffffff9560cede
#3 [ffffd08c4f063b80] _RNvCscb18lrEyTSA_10rust_panic10area_in_hp at ffffffffc07fe107
[rust_panic]
#4 [ffffd08c4f063c20] _RNvMCscb18lrEyTSA_10rust_panicNtB2_10HelloPanic8step_two at
ffffffffc07fe160 [rust_panic]
...
crash> sym _RNvCscb18lrEyTSA_10rust_panic10area_in_hp
ffffffffc07fe010 (t) _RNvCscb18lrEyTSA_10rust_panic10area_in_hp [rust_panic]
/root/linux-6.16.3/samples/rust/rust_panic.rs: 22
With the patch:
crash> bt
PID: 3520 TASK: ffff8f240f670000 CPU: 1 COMMAND: "insmod"
#0 [ffffd08c4f063a20] machine_kexec at ffffffff9575e60e
#1 [ffffd08c4f063a40] __crash_kexec at ffffffff958db711
#2 [ffffd08c4f063b00] panic at ffffffff9560cede
#3 [ffffd08c4f063b80] rust_panic::area_in_hp at ffffffffc07fe107 [rust_panic]
#4 [ffffd08c4f063c20] <rust_panic::HelloPanic>::step_two at ffffffffc07fe160
[rust_panic]
...
crash> sym "rust_panic::area_in_hp"
ffffffffc07fe010 (t) rust_panic::area_in_hp [rust_panic]
/root/linux-6.16.3/samples/rust/rust_panic.rs: 22
Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com>
---
symbols.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/symbols.c b/symbols.c
index 052196265be0..7e9f57be7cec 100644
--- a/symbols.c
+++ b/symbols.c
@@ -3277,6 +3277,46 @@ load_module_filter(char *s, int type)
#define AVERAGE_SYMBOL_SIZE (16)
+static size_t rust_demangle_symbol(const char *symbol, char *out, size_t out_size)
+{
+ int i;
+ size_t loc = 0;
+ size_t len = strlen(symbol);
+ char *buf = NULL;
+ /*
+ * Rust symbols always start with _R (v0) or _ZN (legacy)
+ */
+ const char *mangled_rust[] = {
+ "_R",
+ "_ZN",
+ NULL
+ };
+
+ if (!out || out_size < len)
+ return 0;
+
+ for (i = 0; mangled_rust[i]; i++) {
+ size_t sz = strlen(mangled_rust[i]);
+ char *p = memmem(symbol, len, mangled_rust[i], sz);
+ if (p) {
+ loc = p - symbol;
+ if (loc)
+ memcpy(out, symbol, loc);
+ break;
+ }
+ }
+
+ buf = rust_demangle(symbol + loc, DMGL_RUST);
+ if (buf) {
+ memcpy(out + loc, buf, strlen(buf));
+ free(buf);
+ return 1;
+ } else if (loc != 0)
+ memset(out, 0, loc);
+
+ return 0;
+}
+
static int
namespace_ctl(int cmd, struct symbol_namespace *ns, void *nsarg1, void *nsarg2)
{
@@ -3315,9 +3355,14 @@ namespace_ctl(int cmd, struct symbol_namespace *ns, void *nsarg1,
void *nsarg2)
return TRUE;
case NAMESPACE_INSTALL:
+ char demangled[BUFSIZE] = {0};
sp = (struct syment *)nsarg1;
name = (char *)nsarg2;
len = strlen(name)+1;
+ if (rust_demangle_symbol(name, demangled, sizeof(demangled))) {
+ len = strlen(demangled) + 1;
+ name = demangled;
+ }
if ((ns->index + len) >= ns->size) {
if (!(addr = realloc(ns->address, ns->size*2)))
error(FATAL, "symbol name space malloc: %s\n",
--
2.50.1