On Tue, 2018-04-10 at 01:22:06 UTC, Michael Ellerman wrote: > If you build the kernel with CONFIG_RELOCATABLE=n, then install the > modules, rebuild the kernel with CONFIG_RELOCATABLE=y and leave the > old modules installed, we crash something like: > > Unable to handle kernel paging request for data at address > 0xd000000018d66cef > Faulting instruction address: 0xc0000000021ddd08 > Oops: Kernel access of bad area, sig: 11 [#1] > Modules linked in: x_tables autofs4 > CPU: 2 PID: 1 Comm: systemd Not tainted 4.16.0-rc6-gcc_ubuntu_le-g99fec39 #1 > ... > NIP check_version.isra.22+0x118/0x170 > Call Trace: > __ksymtab_xt_unregister_table+0x58/0xfffffffffffffcb8 [x_tables] > (unreliable) > resolve_symbol+0xb4/0x150 > load_module+0x10e8/0x29a0 > SyS_finit_module+0x110/0x140 > system_call+0x58/0x6c > > This happens because since commit 71810db27c1c ("modversions: treat > symbol CRCs as 32 bit quantities"), a relocatable kernel encodes and > handles symbol CRCs differently from a non-relocatable kernel. > > Although it's possible we could try and detect this situation and > handle it, it's much more robust to simply make the state of > CONFIG_RELOCATABLE part of the module vermagic. > > Fixes: 71810db27c1c ("modversions: treat symbol CRCs as 32 bit quantities") > Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
Applied to powerpc fixes. https://git.kernel.org/powerpc/c/73aca179d78eaa11604ba0783a6d8b cheers