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SubjectRe: [PATCH] ACPI / sysfs: fix shift-overflow in GPE flooding quirk mechanism
Hi Wysocki and Brown,
May I know wether you have checked this? Thanks!

On Fri, Dec 22, 2017 at 11:11:10PM +0800, changbin.du@intel.com wrote:
> From: Changbin Du <changbin.du@intel.com>
>
> The ACPI_MASKABLE_GPE_MAX is larger than the number of bits that u64 can
> represent. This result in shift-overflow. So actually we need a bitmap.
>
> [ 1.003153] ======================================================================
> [ 1.003257] UBSAN: Undefined behaviour in drivers/acpi/sysfs.c:849:33
> [ 1.003314] shift exponent 64 is too large for 64-bit type 'long long unsigned int'
> [ 1.003381] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.15.0-rc4+ #40
> [ 1.003436] Hardware name: LENOVO 20HAS02515/20HAS02515, BIOS N1VET36W (1.26 ) 10/03/2017
> [ 1.003504] Call Trace:
> [ 1.003542] dump_stack+0xe3/0x177
> [ 1.003582] ? _atomic_dec_and_lock+0x219/0x219
> [ 1.003653] ubsan_epilogue+0xd/0x4e
> [ 1.003695] __ubsan_handle_shift_out_of_bounds+0x1f8/0x23d
> [ 1.003754] ? __ubsan_handle_load_invalid_value+0x13b/0x13b
> [ 1.003817] ? trace_hardirqs_on_caller+0x1f3/0x370
> [ 1.003868] ? trace_hardirqs_on+0xd/0x10
> [ 1.003917] ? up+0xe9/0x160
> [ 1.003957] ? sugov_should_update_freq+0xa1/0x1f0
> [ 1.004000] ? trace_hardirqs_on+0xd/0x10
> [ 1.004000] acpi_gpe_apply_masked_gpes+0xa4/0x125
> [ 1.004000] ? acpi_gpe_apply_masked_gpes+0xa4/0x125
> [ 1.004000] ? acpi_gpe_set_masked_gpes+0xe3/0xe3
> [ 1.004000] ? acpi_get_table+0x111/0x127
> [ 1.004000] acpi_scan_init+0x299/0x598
> [ 1.004000] ? acpi_match_madt+0xae/0xae
> [ 1.004000] ? sysfs_add_file_mode_ns+0x160/0x320
> [ 1.004000] ? kobject_put+0x23/0x220
> [ 1.004000] ? bus_create_file+0x75/0x90
> [ 1.004000] ? bus_register+0x44a/0x540
> [ 1.004000] ? subsys_register.part.1+0x140/0x140
> [ 1.004000] acpi_init+0x532/0x5d8
> [ 1.004000] ? acpi_sleep_proc_init+0x36/0x36
> [ 1.004000] ? console_trylock+0x60/0x60
> [ 1.004000] ? sysfs_add_file_mode_ns+0x160/0x320
> [ 1.004000] ? sysfs_create_file_ns+0x56/0x80
> [ 1.004000] ? video_setup+0x13c/0x13c
> [ 1.004000] ? fb_console_init+0x16c/0x1fc
> [ 1.004000] ? acpi_sleep_proc_init+0x36/0x36
> [ 1.004000] do_one_initcall+0xae/0x282
> [ 1.004000] ? initcall_blacklisted+0x1c0/0x1c0
> [ 1.004000] ? up_write+0x92/0x100
> [ 1.004000] ? down_write_nested+0x110/0x110
> [ 1.004000] ? kasan_unpoison_shadow+0x35/0x50
> [ 1.004000] kernel_init_freeable+0x4af/0x573
> [ 1.004000] ? start_kernel+0x6b1/0x6b1
> [ 1.004000] ? rest_init+0x100/0x100
> [ 1.004000] kernel_init+0x13/0x13d
> [ 1.004000] ? rest_init+0x100/0x100
> [ 1.004000] ? rest_init+0x100/0x100
> [ 1.004000] ret_from_fork+0x24/0x30
> [ 1.004000] ======================================================================
>
> Fixes: 9c4aa1eecb48 ("ACPI / sysfs: Provide quirk mechanism to prevent GPE flooding")
> Signed-off-by: Changbin Du <changbin.du@intel.com>
> ---
> drivers/acpi/sysfs.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c
> index 06a150b..60ade0b 100644
> --- a/drivers/acpi/sysfs.c
> +++ b/drivers/acpi/sysfs.c
> @@ -823,7 +823,7 @@ static ssize_t counter_set(struct kobject *kobj,
> */
> #define ACPI_MASKABLE_GPE_MAX 0x80
>
> -static u64 __initdata acpi_masked_gpes;
> +static __initdata DECLARE_BITMAP(acpi_masked_gpes, ACPI_MASKABLE_GPE_MAX);
>
> static int __init acpi_gpe_set_masked_gpes(char *val)
> {
> @@ -831,7 +831,8 @@ static int __init acpi_gpe_set_masked_gpes(char *val)
>
> if (kstrtou8(val, 0, &gpe) || gpe > ACPI_MASKABLE_GPE_MAX)
> return -EINVAL;
> - acpi_masked_gpes |= ((u64)1<<gpe);
> +
> + set_bit(gpe, acpi_masked_gpes);
>
> return 1;
> }
> @@ -846,7 +847,7 @@ void __init acpi_gpe_apply_masked_gpes(void)
> for (gpe = 0;
> gpe < min_t(u8, ACPI_MASKABLE_GPE_MAX, acpi_current_gpe_count);
> gpe++) {
> - if (acpi_masked_gpes & ((u64)1<<gpe)) {
> + if (test_bit(gpe, acpi_masked_gpes)) {
> status = acpi_get_gpe_device(gpe, &handle);
> if (ACPI_SUCCESS(status)) {
> pr_info("Masking GPE 0x%x.\n", gpe);
> --
> 2.7.4
>

--
Thanks,
Changbin Du

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