Messages in this thread | | | Date | Mon, 13 Apr 2015 18:13:05 -0500 | From | Josh Poimboeuf <> | Subject | Re: [PATCH 2/2] livepatch: Fix the bug if the function name is larger than KSYM_NAME_LEN-1 |
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On Sun, Apr 12, 2015 at 09:15:54PM +0800, Minfei Huang wrote: > For now, the kallsyms will only store the first (KSYM_NAME_LEN-1). The > kallsyms name is same for the function which first (KSYM_NAME_LEN-1) is > same, but the rest is not. > > Then function will never be patched, although function name and address > are provided both. The reason caused this bug is livepatch cannt > recognize the function name. > > Now, livepatch will verify the function name with first (KSYM_NAME_LEN-1) > and address, if provided. Once they are matched, we can confirm that the > patched function is found.
From scripts/kallsyms.c:
if (strlen(str) > KSYM_NAME_LEN) { fprintf(stderr, "Symbol %s too long for kallsyms (%zu vs %d).\n" "Please increase KSYM_NAME_LEN both in kernel and kallsyms.c\n", str, strlen(str), KSYM_NAME_LEN); return -1; }
So I think such a long symbol name wouldn't be added to the kallsyms database in the first place.
-- Josh
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