On Fri, Oct 18, 2024 at 03:57:30PM +0300, Andy Shevchenko wrote: > On Thu, Oct 17, 2024 at 03:03:47PM -0400, Gregory Price wrote: > > walk_system_ram_res_rev() erroneously discards resource flags when > > passing the information to the callback. > > > > This causes systems with IORESOURCE_SYSRAM_DRIVER_MANAGED memory to > > have these resources selected during kexec to store kexec buffers > > if that memory happens to be at placed above normal system ram. > > > > This leads to undefined behavior after reboot. If the kexec buffer > > is never touched, nothing happens. If the kexec buffer is touched, > > it could lead to a crash (like below) or undefined behavior. > > > > Tested on a system with CXL memory expanders with driver managed > > memory, TPM enabled, and CONFIG_IMA_KEXEC=y. Adding printk's > > showed the flags were being discarded and as a result the check > > for IORESOURCE_SYSRAM_DRIVER_MANAGED passes. > > > > find_next_iomem_res: name(System RAM (kmem)) > > start(10000000000) > > end(1034fffffff) > > flags(83000200) > > > > locate_mem_hole_top_down: start(10000000000) end(1034fffffff) flags(0) > > > > [.] BUG: unable to handle page fault for address: ffff89834ffff000 > > Please, cut this down to only important ~3-5 lines as suggested in > the Submitting Patches documentation. > > Yeah, I see that Andrew applied it to hist testing branch, if it's not going to > be updated there, consider above as a hint for the future contributions with > backtraces. > noted, thank you! > -- > With Best Regards, > Andy Shevchenko > >
