Hi Kangjie, Thank you for the patch! Yet something to improve:
[auto build test ERROR on pm/linux-next] [also build test ERROR on v4.20 next-20181224] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Kangjie-Lu/acpi-fix-a-potential-inconsistency-caused-by-double-fetch/20181226-054721 base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next config: x86_64-randconfig-x019-201851 (attached as .config) compiler: gcc-7 (Debian 7.3.0-1) 7.3.0 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 All error/warnings (new ones prefixed by >>): In file included from include/linux/uaccess.h:14:0, from drivers//acpi/custom_method.c:8: drivers//acpi/custom_method.c: In function 'cm_write': >> drivers//acpi/custom_method.c:36:42: error: request for member 'length' in >> something not a structure or union &(struct acpi_table_header *)user_buf->length)) ^ arch/x86/include/asm/uaccess.h:138:41: note: in definition of macro '__inttype' __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) ^ >> drivers//acpi/custom_method.c:35:7: note: in expansion of macro 'get_user' if (get_user(max_size, ^~~~~~~~ arch/x86/include/asm/uaccess.h:138:12: error: first argument to '__builtin_choose_expr' not a constant __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) ^ arch/x86/include/asm/uaccess.h:174:11: note: in expansion of macro '__inttype' register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \ ^~~~~~~~~ >> drivers//acpi/custom_method.c:35:7: note: in expansion of macro 'get_user' if (get_user(max_size, ^~~~~~~~ >> drivers//acpi/custom_method.c:36:42: error: request for member 'length' in >> something not a structure or union &(struct acpi_table_header *)user_buf->length)) ^ arch/x86/include/asm/uaccess.h:180:15: note: in definition of macro 'get_user' : "0" (ptr), "i" (sizeof(*(ptr)))); \ ^~~ >> drivers//acpi/custom_method.c:36:42: error: request for member 'length' in >> something not a structure or union &(struct acpi_table_header *)user_buf->length)) ^ arch/x86/include/asm/uaccess.h:180:35: note: in definition of macro 'get_user' : "0" (ptr), "i" (sizeof(*(ptr)))); \ ^~~ >> drivers//acpi/custom_method.c:36:42: error: request for member 'length' in >> something not a structure or union &(struct acpi_table_header *)user_buf->length)) ^ arch/x86/include/asm/uaccess.h:181:30: note: in definition of macro 'get_user' (x) = (__force __typeof__(*(ptr))) __val_gu; \ ^~~ drivers//acpi/custom_method.c:59:45: error: request for member 'length' in something not a structure or union (struct acpi_table_header *)(buf + (*ppos))->length = max_size; ^~ vim +/get_user +35 drivers//acpi/custom_method.c > 8 #include <linux/uaccess.h> 9 #include <linux/debugfs.h> 10 #include <linux/acpi.h> 11 12 #include "internal.h" 13 14 #define _COMPONENT ACPI_SYSTEM_COMPONENT 15 ACPI_MODULE_NAME("custom_method"); 16 MODULE_LICENSE("GPL"); 17 18 static struct dentry *cm_dentry; 19 20 /* /sys/kernel/debug/acpi/custom_method */ 21 22 static ssize_t cm_write(struct file *file, const char __user * user_buf, 23 size_t count, loff_t *ppos) 24 { 25 static char *buf; 26 static u32 max_size; 27 static u32 uncopied_bytes; 28 29 acpi_status status; 30 31 if (!(*ppos)) { 32 /* parse the table header to get the table length */ 33 if (count <= sizeof(struct acpi_table_header)) 34 return -EINVAL; > 35 if (get_user(max_size, > 36 &(struct acpi_table_header *)user_buf->length)) 37 return -EFAULT; 38 uncopied_bytes = max_size; 39 buf = kzalloc(max_size, GFP_KERNEL); 40 if (!buf) 41 return -ENOMEM; 42 } 43 44 if (buf == NULL) 45 return -EINVAL; 46 47 if ((*ppos > max_size) || 48 (*ppos + count > max_size) || 49 (*ppos + count < count) || 50 (count > uncopied_bytes)) 51 return -EINVAL; 52 53 if (copy_from_user(buf + (*ppos), user_buf, count)) { 54 kfree(buf); 55 buf = NULL; 56 return -EFAULT; 57 } 58 /* Ensure table length is not changed in the second copy */ 59 (struct acpi_table_header *)(buf + (*ppos))->length = max_size; 60 61 uncopied_bytes -= count; 62 *ppos += count; 63 64 if (!uncopied_bytes) { 65 status = acpi_install_method(buf); 66 kfree(buf); 67 buf = NULL; 68 if (ACPI_FAILURE(status)) 69 return -EINVAL; 70 add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE); 71 } 72 73 return count; 74 } 75 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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