From: Steven Price steven.price@arm.com
[ Upstream commit c02a98753e0a36ba65a05818626fa6adeb4e7c97 ]
If walk_pte_range() is called with a 'end' argument that is beyond the last page of memory (e.g. ~0UL) then the comparison between 'addr' and 'end' will always fail and the loop will be infinite. Instead change the comparison to >= while accounting for overflow.
Link: http://lkml.kernel.org/r/20191218162402.45610-15-steven.price@arm.com Signed-off-by: Steven Price steven.price@arm.com Cc: Albert Ou aou@eecs.berkeley.edu Cc: Alexandre Ghiti alex@ghiti.fr Cc: Andy Lutomirski luto@kernel.org Cc: Ard Biesheuvel ard.biesheuvel@linaro.org Cc: Arnd Bergmann arnd@arndb.de Cc: Benjamin Herrenschmidt benh@kernel.crashing.org Cc: Borislav Petkov bp@alien8.de Cc: Catalin Marinas catalin.marinas@arm.com Cc: Christian Borntraeger borntraeger@de.ibm.com Cc: Dave Hansen dave.hansen@linux.intel.com Cc: David S. Miller davem@davemloft.net Cc: Heiko Carstens heiko.carstens@de.ibm.com Cc: "H. Peter Anvin" hpa@zytor.com Cc: Ingo Molnar mingo@redhat.com Cc: James Hogan jhogan@kernel.org Cc: James Morse james.morse@arm.com Cc: Jerome Glisse jglisse@redhat.com Cc: "Liang, Kan" kan.liang@linux.intel.com Cc: Mark Rutland mark.rutland@arm.com Cc: Michael Ellerman mpe@ellerman.id.au Cc: Paul Burton paul.burton@mips.com Cc: Paul Mackerras paulus@samba.org Cc: Paul Walmsley paul.walmsley@sifive.com Cc: Peter Zijlstra peterz@infradead.org Cc: Ralf Baechle ralf@linux-mips.org Cc: Russell King linux@armlinux.org.uk Cc: Thomas Gleixner tglx@linutronix.de Cc: Vasily Gorbik gor@linux.ibm.com Cc: Vineet Gupta vgupta@synopsys.com Cc: Will Deacon will@kernel.org Cc: Zong Li zong.li@sifive.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- mm/pagewalk.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/pagewalk.c b/mm/pagewalk.c index d48c2a986ea3f..4eb09e0898817 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -16,9 +16,9 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, err = ops->pte_entry(pte, addr, addr + PAGE_SIZE, walk); if (err) break; - addr += PAGE_SIZE; - if (addr == end) + if (addr >= end - PAGE_SIZE) break; + addr += PAGE_SIZE; pte++; }