4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Vlastimil Babka <[email protected]> commit 9df9516940a61d29aedf4d91b483ca6597e7d480 upstream. On 32bit PAE kernels on 64bit hardware with enough physical bits, l1tf_pfn_limit() will overflow unsigned long. This in turn affects max_swapfile_size() and can lead to swapon returning -EINVAL. This has been observed in a 32bit guest with 42 bits physical address size, where max_swapfile_size() overflows exactly to 1 << 32, thus zero, and produces the following warning to dmesg: [ 6.396845] Truncating oversized swap area, only using 0k out of 2047996k Fix this by using unsigned long long instead. Fixes: 17dbca119312 ("x86/speculation/l1tf: Add sysfs reporting for l1tf") Fixes: 377eeaa8e11f ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2") Reported-by: Dominique Leuenberger <[email protected]> Reported-by: Adrian Schroeter <[email protected]> Signed-off-by: Vlastimil Babka <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Acked-by: Andi Kleen <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: "H . Peter Anvin" <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Michal Hocko <[email protected]> Cc: [email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/include/asm/processor.h | 4 ++-- arch/x86/mm/init.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -172,9 +172,9 @@ extern const struct seq_operations cpuin extern void cpu_detect(struct cpuinfo_x86 *c); -static inline unsigned long l1tf_pfn_limit(void) +static inline unsigned long long l1tf_pfn_limit(void) { - return BIT(boot_cpu_data.x86_phys_bits - 1 - PAGE_SHIFT) - 1; + return BIT_ULL(boot_cpu_data.x86_phys_bits - 1 - PAGE_SHIFT) - 1; } extern void early_cpu_init(void); --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -779,7 +779,7 @@ unsigned long max_swapfile_size(void) if (boot_cpu_has_bug(X86_BUG_L1TF)) { /* Limit the swap file size to MAX_PA/2 for L1TF workaround */ - unsigned long l1tf_limit = l1tf_pfn_limit() + 1; + unsigned long long l1tf_limit = l1tf_pfn_limit() + 1; /* * We encode swap offsets also with 3 bits below those for pfn * which makes the usable limit higher. @@ -787,7 +787,7 @@ unsigned long max_swapfile_size(void) #if CONFIG_PGTABLE_LEVELS > 2 l1tf_limit <<= PAGE_SHIFT - SWP_OFFSET_FIRST_BIT; #endif - pages = min_t(unsigned long, l1tf_limit, pages); + pages = min_t(unsigned long long, l1tf_limit, pages); } return pages; }
