[Crash-utility] [PATCH] Fix the segfault issue caused by "dis -s" command
I did some tests on the vmcore with Rust enabled, and found that
the "dis -s" command may cause a segfault:
crash> dis -s _RNvCscb18lrEyTSA_10rust_panic10area_in_hp
Enable debuginfod for this session? (y or [n])
FILE: rust_panic.rs
LINE: 22
Segmentation fault (core dumped) ./crash
/home/lijiang/src/rust/6.16.3-vmcore-rust/vmlinux
/home/lijiang/src/rust/6.16.3-vmcore-rust/vmcore
gdb calltrace:
(gdb) bt
#0 decimal (s=0x0, count=count@entry=0) at tools.c:1113
#1 0x00000000008eea96 in list_source_code (req=0x1081860 <shared_bufs>,
count_entered=0) at kernel.c:1578
#2 cmd_dis () at kernel.c:2052
#3 0x000000000086b468 in exec_command () at main.c:893
#4 0x000000000086b6aa in main_loop () at main.c:840
#5 0x00000000006b950c in captured_main (data=data@entry=0x7ffe049a3bd0) at main.c:1374
#6 gdb_main (args=args@entry=0x7ffe049a3c10) at main.c:1407
#7 0x00000000006b9579 in gdb_main_entry (argc=2, argv=argv@entry=0x7ffe049a3db8) at
main.c:1434
#8 0x000000000090529e in gdb_main_loop (argc=<optimized out>, argc@entry=3,
argv=argv@entry=0x7ffe049a3db8)
at gdb_interface.c:81
#9 0x0000000000438344 in main (argc=3, argv=0x7ffe049a3db8) at main.c:721
(gdb)
This is because the decimal() tried to dereference a NULL pointer in the
list_source_code() path, when the source code is not available. Given
that, let's add a check to fix such cases.
With the patch:
crash> dis -s _RNvCscb18lrEyTSA_10rust_panic10area_in_hp
Enable debuginfod for this session? (y or [n])
FILE: rust_panic.rs
LINE: 22
dis: _RNvCscb18lrEyTSA_10rust_panic10area_in_hp: source code is not available
crash>
Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com>
---
tools.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools.c b/tools.c
index c9305bef7c9c..a9ad18d520d9 100644
--- a/tools.c
+++ b/tools.c
@@ -1110,7 +1110,7 @@ decimal(char *s, int count)
} else
cnt = count;
- for (p = &s[0], digits = 0; *p; p++) {
+ for (p = &s[0], digits = 0; p && *p; p++) {
switch(*p)
{
case '0':
--
2.50.1