On 09/20/2016 01:49 PM, zijun_hu wrote: > From: zijun_hu <zijun_hu@xxxxxxx> > > for ioremap_page_range(), endless loop maybe happen if either of parameter > addr and end is not page aligned, in order to fix this issue and hint range > parameter requirements BUG_ON() checkup are performed firstly > > for ioremap_pte_range(), loop end condition is optimized due to lack of > relevant macro pte_addr_end() > > Signed-off-by: zijun_hu <zijun_hu@xxxxxxx> > --- > lib/ioremap.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/lib/ioremap.c b/lib/ioremap.c > index 86c8911..0058cc8 100644 > --- a/lib/ioremap.c > +++ b/lib/ioremap.c > @@ -64,7 +64,7 @@ static int ioremap_pte_range(pmd_t *pmd, unsigned long addr, > BUG_ON(!pte_none(*pte)); > set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot)); > pfn++; > - } while (pte++, addr += PAGE_SIZE, addr != end); > + } while (pte++, addr += PAGE_SIZE, addr < end); > return 0; > } > > @@ -129,6 +129,7 @@ int ioremap_page_range(unsigned long addr, > int err; > > BUG_ON(addr >= end); > + BUG_ON(!PAGE_ALIGNED(addr | end)); > > start = addr; > phys_addr -= addr; > another approach is provided in another mail thread as below i don't known which is more appropriate From: zijun_hu <zijun_hu@xxxxxxx> Subject: [PATCH 1/1] lib/ioremap.c: avoid endless loop under ioremapping page unaligned ranges endless loop maybe happen if either of parameter addr and end is not page aligned for kernel API function ioremap_page_range() in order to fix this issue and alert improper range parameters to user WARN_ON() checkup and rounding down range lower boundary are performed firstly, loop end condition within ioremap_pte_range() is optimized due to lack of relevant macro pte_addr_end() Signed-off-by: zijun_hu <zijun_hu@xxxxxxx> --- lib/ioremap.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/lib/ioremap.c b/lib/ioremap.c index 86c8911..911bdca 100644 --- a/lib/ioremap.c +++ b/lib/ioremap.c @@ -64,7 +64,7 @@ static int ioremap_pte_range(pmd_t *pmd, unsigned long addr, BUG_ON(!pte_none(*pte)); set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot)); pfn++; - } while (pte++, addr += PAGE_SIZE, addr != end); + } while (pte++, addr += PAGE_SIZE, addr < end && addr >= PAGE_SIZE); return 0; } @@ -129,7 +129,9 @@ int ioremap_page_range(unsigned long addr, int err; BUG_ON(addr >= end); + WARN_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end)); + addr = round_down(addr, PAGE_SIZE); start = addr; phys_addr -= addr; pgd = pgd_offset_k(addr); -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>