copy_from_user does not copy from process-heap
Hello all,
I need a positive reply from you.
I want to copy the user-process-heap to the kernel space memory.
For that, I wrote the following code but it does not copy.
---------------- code --------------
unsigned long length_of_heap_vma = < length of vma pointing to process-heap > ;
void * kernel_mem = (void *) kmalloc(length_of_heap_vma,GFP_KERNEL);
unsigned long bytes_not_copied = 0;
bytes_not_copied = copy_from_user(kernel_mem,(void *)vm->vma_start,length_of_heap_vma);//vm points to process heap
printk("failed to copy %ld bytes.",bytes_not_copied); //it always displays a non-zero value.
---------------- end of code --------
now the PROBLEM is that - the code successfuly compiles, but when I execute it, it copies not a single byte and
bytes_not-copied always becomes equal to length_of_heap_vma. No compile-time or execution-time error occurs.
(note: my process has the following dynamic memory in user-part:
int * p = (int*) malloc(5 * sizeof(int));
for(i=0;i<5;i++)<br />
p[i]= i;
)
Comments
-
Please provide the entire kernel module code if possible.0
-
Hi...
There is a chance you're not copying from the right user space address. May I know how do you determine the source address in the related user process address space you want to copy from?0 -
Hi
void * kernel_mem = (void *) kmalloc(length_of_heap_vma,GFP_KERNEL);
i think this line is the problem
make void * kernel_mem to char * kernel_mem
it should work . Eagerly waiting for your reply0
Categories
- All Categories
- 112 LFX Mentorship
- 112 LFX Mentorship: Linux Kernel
- 604 Linux Foundation IT Professional Programs
- 315 Cloud Engineer IT Professional Program
- 139 Advanced Cloud Engineer IT Professional Program
- 52 DevOps Engineer IT Professional Program
- 67 Cloud Native Developer IT Professional Program
- 4 Express Training Courses
- 4 Express Courses - Discussion Forum
- 5.3K Training Courses
- 17 LFC110 Class Forum - Discontinued
- 8 LFC131 Class Forum
- 30 LFD102 Class Forum
- 178 LFD103 Class Forum
- LFD110 Class Forum
- 24 LFD121 Class Forum
- LFD133 Class Forum
- 2 LFD137 Class Forum
- 62 LFD201 Class Forum
- 2 LFD210 Class Forum
- 1 LFD210-CN Class Forum
- 1 LFD213 Class Forum - Discontinued
- 127 LFD232 Class Forum - Discontinued
- LFD233 Class Forum
- LFD237 Class Forum
- 22 LFD254 Class Forum
- 643 LFD259 Class Forum
- 107 LFD272 Class Forum
- 1 LFD272-JP クラス フォーラム
- 4 LFD273 Class Forum
- 1 LFS101 Class Forum
- LFS112 Class Forum
- LFS116 Class Forum
- LFS118 Class Forum
- LFS142 Class Forum
- LFS144 Class Forum
- 2 LFS145 Class Forum
- LFS146 Class Forum
- LFS151 Class Forum
- LFS157 Class Forum
- LFS158 Class Forum
- LFS162 Class Forum
- LFS166 Class Forum
- LFS167 Class Forum
- LFS170 Class Forum
- LFS171 Class Forum
- LFS178 Class Forum
- LFS180 Class Forum
- LFS182 Class Forum
- LFS183 Class Forum
- 28 LFS200 Class Forum
- 735 LFS201 Class Forum - Discontinued
- 1 LFS201-JP クラス フォーラム
- 13 LFS203 Class Forum
- 98 LFS207 Class Forum
- 299 LFS211 Class Forum
- 54 LFS216 Class Forum
- 47 LFS241 Class Forum
- 41 LFS242 Class Forum
- 36 LFS243 Class Forum
- 12 LFS244 Class Forum
- LFS245 Class Forum
- 41 LFS250 Class Forum
- 1 LFS250-JP クラス フォーラム
- LFS251 Class Forum
- 141 LFS253 Class Forum
- LFS254 Class Forum
- LFS255 Class Forum
- 2 LFS256 Class Forum
- LFS257 Class Forum
- 1.2K LFS258 Class Forum
- 9 LFS258-JP クラス フォーラム
- 109 LFS260 Class Forum
- 144 LFS261 Class Forum
- 39 LFS262 Class Forum
- 82 LFS263 Class Forum - Discontinued
- 15 LFS264 Class Forum - Discontinued
- 11 LFS266 Class Forum - Discontinued
- 20 LFS267 Class Forum
- 18 LFS268 Class Forum
- 26 LFS269 Class Forum
- 198 LFS272 Class Forum
- 1 LFS272-JP クラス フォーラム
- LFS274 Class Forum
- 3 LFS281 Class Forum
- LFW111 Class Forum
- 254 LFW211 Class Forum
- 173 LFW212 Class Forum
- 9 SKF100 Class Forum
- SKF200 Class Forum
- 781 Hardware
- 198 Drivers
- 68 I/O Devices
- 37 Monitors
- 95 Multimedia
- 174 Networking
- 87 Printers & Scanners
- 83 Storage
- 742 Linux Distributions
- 80 Debian
- 66 Fedora
- 15 Linux Mint
- 13 Mageia
- 23 openSUSE
- 143 Red Hat Enterprise
- 31 Slackware
- 13 SUSE Enterprise
- 347 Ubuntu
- 450 Linux System Administration
- 31 Cloud Computing
- 69 Command Line/Scripting
- Github systems admin projects
- 89 Linux Security
- 76 Network Management
- 101 System Management
- 46 Web Management
- 51 Mobile Computing
- 18 Android
- 23 Development
- 1.2K New to Linux
- 1K Getting Started with Linux
- 355 Off Topic
- 109 Introductions
- 167 Small Talk
- 18 Study Material
- 504 Programming and Development
- 283 Kernel Development
- 203 Software Development
- 844 Software
- 210 Applications
- 180 Command Line
- 3 Compiling/Installing
- 107 Games
- 308 Installation
- 51 All In Program
- 51 All In Forum
Upcoming Training
-
August 20, 2018
Kubernetes Administration (LFS458)
-
August 20, 2018
Linux System Administration (LFS301)
-
August 27, 2018
Open Source Virtualization (LFS462)
-
August 27, 2018
Linux Kernel Debugging and Security (LFD440)