Messages in this thread | | | Date | Thu, 19 Mar 2009 08:46:16 +0100 | From | Ingo Molnar <> | Subject | Re: oops in tracepoint_update_probe_range() |
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* Lai Jiangshan <laijs@cn.fujitsu.com> wrote:
> Ingo Molnar wrote: > > * Jaswinder Singh Rajput <jaswinder@kernel.org> wrote: > > > >> Good: f4c3c4cdb1de232 > >> Bad : 1e08816af0bc345 > >> > >> Config: > >> http://userweb.kernel.org/~jaswinder/oops_20090318/config-hpdv5-tip-bad-20090318 > >> > >> oops: > >> http://userweb.kernel.org/~jaswinder/oops_20090318/oops_page1.jpg > >> http://userweb.kernel.org/~jaswinder/oops_20090318/oops_page2.jpg > >> http://userweb.kernel.org/~jaswinder/oops_20090318/oops_page3.jpg > >> http://userweb.kernel.org/~jaswinder/oops_20090318/oops_page4.jpg > >> > >> <freeze> > > > > Steve, Frederic - the crashes above are in: > > > > tracepoint_update_probe_range() > > > > in a modular kernel apparently. > > > > > > I look up the jpg files, this oops is occurred when a new module is > being loaded. > > tracepoint_module_notify() is added by Mathieu Desnoyers on the > suggestion of me. > > tracepoint_update_probe_range() and tracepoint_module_notify() > can not trigger this oops if the arguments are correct. > > If @begin is NULL, @end is NULL too, it's ensued by kernel/module.c. > > load_module(...): > mod->tracepoints = section_objs(hdr, sechdrs, secstrings, > "__tracepoints", > sizeof(*mod->tracepoints), > &mod->num_tracepoints); > static void *section_objs(...) > { > unsigned int sec = find_sec(hdr, sechdrs, secstrings, name); > > /* Section 0 has sh_addr 0 and sh_size 0. */ > *num = sechdrs[sec].sh_size / object_size; > return (void *)sechdrs[sec].sh_addr; > } > > If the module has not "__tracepoints" section, find_sec() returns 0. > So I think, sechdrs[0].sh_size is corrupted. > > Is the following fix fixed the oops for you? > --- > diff --git a/kernel/module.c b/kernel/module.c > index 7fa134e..2ee47ff 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -1950,6 +1950,7 @@ static noinline struct module *load_module(void __user *umod, > sechdrs = (void *)hdr + hdr->e_shoff; > secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; > sechdrs[0].sh_addr = 0; > + sechdrs[0].sh_size = 0; > > for (i = 1; i < hdr->e_shnum; i++) { > if (sechdrs[i].sh_type != SHT_NOBITS
Jaswinder, could you please try the fix from Lai, but first do:
git revert ec625cb # tracepoints: dont update zero-sized tracepoint sections git revert 09933a1 # tracing: fix oops in tracepoint_update_probe_range()
?
Ingo
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