On Wed, Jan 05, 2022, Peter Xu wrote: > On Wed, Jan 05, 2022 at 09:33:37AM +0530, Nikunj A Dadhania wrote: > > With TDP MMU being the default now, access to mmu_rmaps_stat debugfs > > file causes following oops: > > > > BUG: kernel NULL pointer dereference, address: 0000000000000000 > > PGD 0 P4D 0 > > Oops: 0000 [#1] PREEMPT SMP NOPTI > > CPU: 7 PID: 3185 Comm: cat Not tainted 5.16.0-rc4+ #204 > > RIP: 0010:pte_list_count+0x6/0x40 > > Call Trace: > > <TASK> > > ? kvm_mmu_rmaps_stat_show+0x15e/0x320 > > seq_read_iter+0x126/0x4b0 > > ? aa_file_perm+0x124/0x490 > > seq_read+0xf5/0x140 > > full_proxy_read+0x5c/0x80 > > vfs_read+0x9f/0x1a0 > > ksys_read+0x67/0xe0 > > __x64_sys_read+0x19/0x20 > > do_syscall_64+0x3b/0xc0 > > entry_SYSCALL_64_after_hwframe+0x44/0xae > > RIP: 0033:0x7fca6fc13912 > > > > Return early when rmaps are not present. > > > > Reported-by: Vasant Hegde <vasant.hegde@xxxxxxx> > > Tested-by: Vasant Hegde <vasant.hegde@xxxxxxx> > > Signed-off-by: Nikunj A Dadhania <nikunj@xxxxxxx> > > --- Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
