On Fri, Oct 04, 2024 at 11:12:16PM +0530, Manas via B4 Relay wrote: > From: Manas <manas18244@xxxxxxxxxxx> > > syzbot has pointed to a possible null pointer dereference in > pfnmap_lockdep_assert. vm_file member of vm_area_struct is being > dereferenced without any checks. > > This fix assigns mapping only if vm_file is not NULL. > > Reported-by: syzbot+093d096417e7038a689b@xxxxxxxxxxxxxxxxxxxxxxxxx > Closes: https://syzkaller.appspot.com/bug?extid=093d096417e7038a689b > --- > This bug[1] triggers a general protection fault in follow_pfnmap_start > function. An assertion pfnmap_lockdep_assert inside this function > dereferences vm_file member of vm_area_struct. And panic gets triggered > when vm_file is NULL. > > This patch assigns mapping only if vm_file is not NULL. > > [1] https://syzkaller.appspot.com/bug?extid=093d096417e7038a689b > > Signed-off-by: Manas <manas18244@xxxxxxxxxxx> Reviewed-by: Peter Xu <peterx@xxxxxxxxxx> -- Peter Xu
