On 13/06/17 21:51, Andrew Cooper wrote: > A symndx of STN_UNDEF is special, and means a symbol value of 0. > > There is no real symbol data for it, so avoid tripping over a NULL pointer > with "elf->sym[symndx].sym->st_value". > > Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com> > --- > CC: Konrad Rzeszutek Wilk <konrad.w...@oracle.com> > CC: Ross Lagerwall <ross.lagerw...@citrix.com> > CC: Jan Beulich <jbeul...@suse.com> > CC: Stefano Stabellini <sstabell...@kernel.org> > CC: Julien Grall <julien.gr...@arm.com> > > Functionally tested on x86, but both arm variants look to suffer from the same > issue. Compile tested on all architectures. > > TODO: Figure out how my livepatch has a STN_UNDEF relocation...
On second thoughts, maybe STN_UNDEF symbols should be a hard failure. (XEN) livepatch: live: Applying 1 functions (XEN) ----[ Xen-4.10-unstable x86_64 debug=y Not tainted ]---- (XEN) CPU: 3 (XEN) RIP: e008:[<0000000000000000>] 0000000000000000 In this case, the hook function hasn't been wired up correctly, which causes apply_payload() to fall over a NULL data->load_funcs[i](); As for why the STN_UNDEF symbol, it comes from an assembly hook function missing a .type attribute. Still, Xen shouldn't crash when it encounters one. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
