| Message ID | 20220808084640.3165368-1-sudeep.holla@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: cacheinfo: Fix incorrect assignment of signed error value to unsigned fw_level | expand |
Hi Will, On Mon, Aug 08, 2022 at 09:46:40AM +0100, Sudeep Holla wrote: > Though acpi_find_last_cache_level() always returned signed value and the > document states it will return any errors caused by lack of a PPTT table, > it never returned negative values before. > > Commit 0c80f9e165f8 ("ACPI: PPTT: Leave the table mapped for the runtime usage") > however changed it by returning -ENOENT if no PPTT was found. The value > returned from acpi_find_last_cache_level() is then assigned to unsigned > fw_level. > > It will result in the number of cache leaves calculated incorrectly as > a huge value which will then cause the following warning from __alloc_pages > as the order would be great than MAX_ORDER because of incorrect and huge > cache leaves value. > > | WARNING: CPU: 0 PID: 1 at mm/page_alloc.c:5407 __alloc_pages+0x74/0x314 > | Modules linked in: > | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-10393-g7c2a8d3ac4c0 #73 > | pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > | pc : __alloc_pages+0x74/0x314 > | lr : alloc_pages+0xe8/0x318 > | Call trace: > | __alloc_pages+0x74/0x314 > | alloc_pages+0xe8/0x318 > | kmalloc_order_trace+0x68/0x1dc > | __kmalloc+0x240/0x338 > | detect_cache_attributes+0xe0/0x56c > | update_siblings_masks+0x38/0x284 > | store_cpu_topology+0x78/0x84 > | smp_prepare_cpus+0x48/0x134 > | kernel_init_freeable+0xc4/0x14c > | kernel_init+0x2c/0x1b4 > | ret_from_fork+0x10/0x20 > > Fix the same by changing fw_level to be signed integer and return the > error from init_cache_level() early in case of error. > Can you pick up this for next round of fixes ? The original report can be found @[1]
On Mon, 8 Aug 2022 09:46:40 +0100, Sudeep Holla wrote: > Though acpi_find_last_cache_level() always returned signed value and the > document states it will return any errors caused by lack of a PPTT table, > it never returned negative values before. > > Commit 0c80f9e165f8 ("ACPI: PPTT: Leave the table mapped for the runtime usage") > however changed it by returning -ENOENT if no PPTT was found. The value > returned from acpi_find_last_cache_level() is then assigned to unsigned > fw_level. > > [...] Applied to arm64 (for-next/fixes), thanks! [1/1] arm64: cacheinfo: Fix incorrect assignment of signed error value to unsigned fw_level https://git.kernel.org/arm64/c/e75d18cecbb3 Cheers,
diff --git a/arch/arm64/kernel/cacheinfo.c b/arch/arm64/kernel/cacheinfo.c index 587543c6c51c..97c42be71338 100644 --- a/arch/arm64/kernel/cacheinfo.c +++ b/arch/arm64/kernel/cacheinfo.c @@ -45,7 +45,8 @@ static void ci_leaf_init(struct cacheinfo *this_leaf, int init_cache_level(unsigned int cpu) { - unsigned int ctype, level, leaves, fw_level; + unsigned int ctype, level, leaves; + int fw_level; struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu); for (level = 1, leaves = 0; level <= MAX_CACHE_LEVEL; level++) { @@ -63,6 +64,9 @@ int init_cache_level(unsigned int cpu) else fw_level = acpi_find_last_cache_level(cpu); + if (fw_level < 0) + return fw_level; + if (level < fw_level) { /* * some external caches not specified in CLIDR_EL1
Though acpi_find_last_cache_level() always returned signed value and the document states it will return any errors caused by lack of a PPTT table, it never returned negative values before. Commit 0c80f9e165f8 ("ACPI: PPTT: Leave the table mapped for the runtime usage") however changed it by returning -ENOENT if no PPTT was found. The value returned from acpi_find_last_cache_level() is then assigned to unsigned fw_level. It will result in the number of cache leaves calculated incorrectly as a huge value which will then cause the following warning from __alloc_pages as the order would be great than MAX_ORDER because of incorrect and huge cache leaves value. | WARNING: CPU: 0 PID: 1 at mm/page_alloc.c:5407 __alloc_pages+0x74/0x314 | Modules linked in: | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-10393-g7c2a8d3ac4c0 #73 | pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) | pc : __alloc_pages+0x74/0x314 | lr : alloc_pages+0xe8/0x318 | Call trace: | __alloc_pages+0x74/0x314 | alloc_pages+0xe8/0x318 | kmalloc_order_trace+0x68/0x1dc | __kmalloc+0x240/0x338 | detect_cache_attributes+0xe0/0x56c | update_siblings_masks+0x38/0x284 | store_cpu_topology+0x78/0x84 | smp_prepare_cpus+0x48/0x134 | kernel_init_freeable+0xc4/0x14c | kernel_init+0x2c/0x1b4 | ret_from_fork+0x10/0x20 Fix the same by changing fw_level to be signed integer and return the error from init_cache_level() early in case of error. Reported-and-Tested-by: Bruno Goncalves <bgoncalv@redhat.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> --- arch/arm64/kernel/cacheinfo.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)