https://bugzilla.kernel.org/show_bug.cgi?id=216073 --- Comment #18 from willy@xxxxxxxxxxxxx --- On Sun, Jun 12, 2022 at 12:43:45PM -0600, Yu Zhao wrote: > On Sun, Jun 12, 2022 at 12:05 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > > > On Sun, Jun 12, 2022 at 11:59:58AM -0600, Yu Zhao wrote: > > > Please let me know if there is something we want to test -- I can > > > reproduce the problem reliably: > > > > > > ------------[ cut here ]------------ > > > kernel BUG at mm/usercopy.c:101! > > > > The line right before cut here would have been nice ;-) > > Right. > > $ grep usercopy: > usercopy: Kernel memory exposure attempt detected from vmalloc (offset > 2882303761517129920, size 11)! > usercopy: Kernel memory exposure attempt detected from vmalloc (offset > 8574853690513436864, size 11)! > usercopy: Kernel memory exposure attempt detected from vmalloc (offset > 7998392938210013376, size 11)! That's a different problem. And, er, what? How on earth do we have an offset that big?! struct vm_struct *area = find_vm_area(ptr); offset = ptr - area->addr; if (offset + n > get_vm_area_size(area)) usercopy_abort("vmalloc", NULL, to_user, offset, n); That first offset is 0x2800'0000'0000'30C0 You said it was easy to replicate; can you add: printk("addr:%px ptr:%px\n", area->addr, ptr); so that we can start to understand how we end up with such a bogus offset? -- You may reply to this email to add a comment. You are receiving this mail because: You are watching someone on the CC list of the bug.
