diff options
| author | Vlastimil Babka <[email protected]> | 2018-08-20 11:58:35 +0200 |
|---|---|---|
| committer | Thomas Gleixner <[email protected]> | 2018-08-20 18:04:42 +0200 |
| commit | 9df9516940a61d29aedf4d91b483ca6597e7d480 (patch) | |
| tree | 446dddbc72dc1059d59be9c4e49f1d6745db1537 | |
| parent | dc76803e57cc86589c4efcb5362918f9b0c0436f (diff) | |
x86/speculation/l1tf: Fix overflow in l1tf_pfn_limit() on 32bit
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]
| -rw-r--r-- | arch/x86/include/asm/processor.h | 4 | ||||
| -rw-r--r-- | arch/x86/mm/init.c | 4 |
2 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 682286aca881..a0a52274cb4a 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -181,9 +181,9 @@ extern const struct seq_operations cpuinfo_op; 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); diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index acfab322fbe0..02de3d6065c4 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -923,7 +923,7 @@ 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. @@ -931,7 +931,7 @@ 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; } |