[Crash-utility] Re: [PATCH] Fix infinite loop during module symbols initialization

I can also reproduce this issue on 6.13.0-rc2 machine. The mod_symname_hash_install() function missed the case if one spn was installed 2 more times, which as a result, will cause the infinite loop. The reason for installing 2 more times is because the addresses overlap between 2 kernel modules. See the following: crash> sym -l ffffffffc0800000 MODULE TEXT START: qemu_fw_cfg ffffffffc0800000 (t) __pfx_fw_cfg_sysfs_attr_show ffffffffc0800010 (t) fw_cfg_sysfs_attr_show ... ffffffffc0801000 MODULE TEXT START: serio_raw ffffffffc0801000 (t) __pfx_serio_raw_poll ffffffffc0801000 MODULE TEXT END: qemu_fw_cfg ... ffffffffc0802000 MODULE TEXT END: serio_raw For module qemu_fw_cfg, 3 symbols of ffffffffc0801000 will be installed. Then for module serio_raw, 3 symbols of ffffffffc0801000 will be reinstalled. Due to the lack of repeat symbol check, there will be symbol reinstall, and infinite loop: sp->name_hash_next = spn; <<----- name_hash_next point to itself if sp==spn I think Kazu's "base + size - 1" solution is reasonable, this will let qemu_fw_cfg install range from ffffffffc0800000 to (ffffffffc0801000-1), so no overlap for 2 modules. In addition, I'd like to add the following code as well, to skip if a symbol has already been installed: diff --git a/symbols.c b/symbols.c index a26bdc1..e1a62bb 100644 --- a/symbols.c +++ b/symbols.c @@ -1233,6 +1233,9 @@ mod_symname_hash_install(struct syment *spn) return; } for (; sp; sp = sp->name_hash_next) { + if (spn == sp) + return; + if (!sp->name_hash_next || spn->value < sp->name_hash_next->value) { spn->name_hash_next = sp->name_hash_next; What do you think?