| Message ID | 20240924074341.37272-1-qiwu.chen@transsion.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v4,1/2] panic: add option to dump task maps info in panic_print | expand |
On 09/24, qiwu.chen wrote: > > +EXPORT_SYMBOL(get_vma_name); Why? > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -3566,6 +3566,10 @@ static inline bool range_in_vma(struct vm_area_struct *vma, > #ifdef CONFIG_MMU > pgprot_t vm_get_page_prot(unsigned long vm_flags); > void vma_set_page_prot(struct vm_area_struct *vma); > +void get_vma_name(struct vm_area_struct *vma, > + const struct path **path, > + const char **name, > + const char **name_fmt); > #else You didn't move get_vma_name() from fs/proc/task_mmu.c, so it also depends on CONFIG_PROC_FS. > +/* > + * This function is called in panic proccess if the PANIC_PRINT_TASK_MAPS_INFO > + * flag is specified in panic_print, which is helpful to debug panic issues due > + * to an unhandled falut in user mode such as kill init. > + */ > +static void dump_task_maps_info(struct task_struct *tsk) > +{ > + struct pt_regs *user_ret = task_pt_regs(tsk); > + struct mm_struct *mm = tsk->mm; > + struct vm_area_struct *vma; > + > + if (!mm || !user_mode(user_ret)) > + return; > + > + pr_info("Dump task %s:%d maps start\n", tsk->comm, task_pid_nr(tsk)); > + mmap_read_lock(mm); > + VMA_ITERATOR(vmi, mm, 0); > + for_each_vma(vmi, vma) { > + int flags = vma->vm_flags; > + unsigned long long pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT; > + const struct path *path; > + const char *name_fmt, *name; > + char name_buf[SZ_256]; > + > + get_vma_name(vma, &path, &name, &name_fmt); So this code won't compile if CONFIG_MMU=n ? > + if (path) { > + name = d_path(path, name_buf, sizeof(name_buf)); > + name = IS_ERR(name) ? "?" : name; perhaps this needs mangle_path() ... > + } else if (name || name_fmt) { > + snprintf(name_buf, sizeof(name_buf), name_fmt ?: "%s", name); > + name = name_buf; > + } Why not } else if (name_fmt) { snprintf(name_buf, sizeof(name_buf), name_fmt, name); name = name_buf; } ? > + if (name) > + pr_info("%08lx-%08lx %c%c%c%c %08llx %s\n", > + vma->vm_start, vma->vm_end, > + flags & VM_READ ? 'r' : '-', > + flags & VM_WRITE ? 'w' : '-', > + flags & VM_EXEC ? 'x' : '-', > + flags & VM_MAYSHARE ? 's' : 'p', > + pgoff, name); I don't really understand why you skip vma if !name... Oleg.
Hi qiwu.chen, kernel test robot noticed the following build errors: [auto build test ERROR on arm64/for-next/core] [also build test ERROR on brauner-vfs/vfs.all akpm-mm/mm-everything linus/master v6.11 next-20240924] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/qiwu-chen/arm64-show-signal-info-for-global-init/20240924-154508 base: https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core patch link: https://lore.kernel.org/r/20240924074341.37272-1-qiwu.chen%40transsion.com patch subject: [PATCH v4 1/2] panic: add option to dump task maps info in panic_print config: arm-stm32_defconfig (https://download.01.org/0day-ci/archive/20240924/202409242252.cefLq5jM-lkp@intel.com/config) compiler: arm-linux-gnueabi-gcc (GCC) 14.1.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240924/202409242252.cefLq5jM-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202409242252.cefLq5jM-lkp@intel.com/ All errors (new ones prefixed by >>): kernel/panic.c: In function 'dump_task_maps_info': >> kernel/panic.c:235:17: error: implicit declaration of function 'get_vma_name'; did you mean 'arch_vma_name'? [-Wimplicit-function-declaration] 235 | get_vma_name(vma, &path, &name, &name_fmt); | ^~~~~~~~~~~~ | arch_vma_name vim +235 kernel/panic.c 210 211 /* 212 * This function is called in panic proccess if the PANIC_PRINT_TASK_MAPS_INFO 213 * flag is specified in panic_print, which is helpful to debug panic issues due 214 * to an unhandled falut in user mode such as kill init. 215 */ 216 static void dump_task_maps_info(struct task_struct *tsk) 217 { 218 struct pt_regs *user_ret = task_pt_regs(tsk); 219 struct mm_struct *mm = tsk->mm; 220 struct vm_area_struct *vma; 221 222 if (!mm || !user_mode(user_ret)) 223 return; 224 225 pr_info("Dump task %s:%d maps start\n", tsk->comm, task_pid_nr(tsk)); 226 mmap_read_lock(mm); 227 VMA_ITERATOR(vmi, mm, 0); 228 for_each_vma(vmi, vma) { 229 int flags = vma->vm_flags; 230 unsigned long long pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT; 231 const struct path *path; 232 const char *name_fmt, *name; 233 char name_buf[SZ_256]; 234 > 235 get_vma_name(vma, &path, &name, &name_fmt); 236 if (path) { 237 name = d_path(path, name_buf, sizeof(name_buf)); 238 name = IS_ERR(name) ? "?" : name; 239 } else if (name || name_fmt) { 240 snprintf(name_buf, sizeof(name_buf), name_fmt ?: "%s", name); 241 name = name_buf; 242 } 243 244 if (name) 245 pr_info("%08lx-%08lx %c%c%c%c %08llx %s\n", 246 vma->vm_start, vma->vm_end, 247 flags & VM_READ ? 'r' : '-', 248 flags & VM_WRITE ? 'w' : '-', 249 flags & VM_EXEC ? 'x' : '-', 250 flags & VM_MAYSHARE ? 's' : 'p', 251 pgoff, name); 252 253 } 254 mmap_read_unlock(mm); 255 pr_info("Dump task %s:%d maps end\n", tsk->comm, task_pid_nr(tsk)); 256 } 257
Hi qiwu.chen,
kernel test robot noticed the following build errors:
[auto build test ERROR on arm64/for-next/core]
[also build test ERROR on brauner-vfs/vfs.all akpm-mm/mm-everything linus/master v6.11 next-20240924]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/qiwu-chen/arm64-show-signal-info-for-global-init/20240924-154508
base: https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
patch link: https://lore.kernel.org/r/20240924074341.37272-1-qiwu.chen%40transsion.com
patch subject: [PATCH v4 1/2] panic: add option to dump task maps info in panic_print
config: arm-allnoconfig (https://download.01.org/0day-ci/archive/20240924/202409242208.SqjERCDw-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 8663a75fa2f31299ab8d1d90288d9df92aadee88)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240924/202409242208.SqjERCDw-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409242208.SqjERCDw-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from kernel/panic.c:15:
In file included from include/linux/kgdb.h:19:
In file included from include/linux/kprobes.h:28:
In file included from include/linux/ftrace.h:13:
In file included from include/linux/kallsyms.h:13:
In file included from include/linux/mm.h:2232:
include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
514 | return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
| ~~~~~~~~~~~ ^ ~~~
>> kernel/panic.c:235:3: error: call to undeclared function 'get_vma_name'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
235 | get_vma_name(vma, &path, &name, &name_fmt);
| ^
1 warning and 1 error generated.
vim +/get_vma_name +235 kernel/panic.c
210
211 /*
212 * This function is called in panic proccess if the PANIC_PRINT_TASK_MAPS_INFO
213 * flag is specified in panic_print, which is helpful to debug panic issues due
214 * to an unhandled falut in user mode such as kill init.
215 */
216 static void dump_task_maps_info(struct task_struct *tsk)
217 {
218 struct pt_regs *user_ret = task_pt_regs(tsk);
219 struct mm_struct *mm = tsk->mm;
220 struct vm_area_struct *vma;
221
222 if (!mm || !user_mode(user_ret))
223 return;
224
225 pr_info("Dump task %s:%d maps start\n", tsk->comm, task_pid_nr(tsk));
226 mmap_read_lock(mm);
227 VMA_ITERATOR(vmi, mm, 0);
228 for_each_vma(vmi, vma) {
229 int flags = vma->vm_flags;
230 unsigned long long pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
231 const struct path *path;
232 const char *name_fmt, *name;
233 char name_buf[SZ_256];
234
> 235 get_vma_name(vma, &path, &name, &name_fmt);
236 if (path) {
237 name = d_path(path, name_buf, sizeof(name_buf));
238 name = IS_ERR(name) ? "?" : name;
239 } else if (name || name_fmt) {
240 snprintf(name_buf, sizeof(name_buf), name_fmt ?: "%s", name);
241 name = name_buf;
242 }
243
244 if (name)
245 pr_info("%08lx-%08lx %c%c%c%c %08llx %s\n",
246 vma->vm_start, vma->vm_end,
247 flags & VM_READ ? 'r' : '-',
248 flags & VM_WRITE ? 'w' : '-',
249 flags & VM_EXEC ? 'x' : '-',
250 flags & VM_MAYSHARE ? 's' : 'p',
251 pgoff, name);
252
253 }
254 mmap_read_unlock(mm);
255 pr_info("Dump task %s:%d maps end\n", tsk->comm, task_pid_nr(tsk));
256 }
257
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 8337d0fed311..f76709deef6c 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4253,6 +4253,7 @@ bit 5: print all printk messages in buffer bit 6: print all CPUs backtrace (if available in the arch) bit 7: print only tasks in uninterruptible (blocked) state + bit 8: print task maps info *Be aware* that this option may print a _lot_ of lines, so there are risks of losing older messages in the log. Use this option carefully, maybe worth to setup a diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index f8bc1630eba0..558e365b76a9 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -872,6 +872,7 @@ bit 4 print ftrace buffer bit 5 print all printk messages in buffer bit 6 print all CPUs backtrace (if available in the arch) bit 7 print only tasks in uninterruptible (blocked) state +bit 8 print task maps info ===== ============================================ So for example to print tasks and memory info on panic, user can:: diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index ade74a396968..37169ae36542 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -240,7 +240,7 @@ static int do_maps_open(struct inode *inode, struct file *file, sizeof(struct proc_maps_private)); } -static void get_vma_name(struct vm_area_struct *vma, +void get_vma_name(struct vm_area_struct *vma, const struct path **path, const char **name, const char **name_fmt) @@ -300,6 +300,7 @@ static void get_vma_name(struct vm_area_struct *vma, return; } } +EXPORT_SYMBOL(get_vma_name); static void show_vma_header_prefix(struct seq_file *m, unsigned long start, unsigned long end, diff --git a/include/linux/mm.h b/include/linux/mm.h index 13bff7cf03b7..2fa403aae1de 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3566,6 +3566,10 @@ static inline bool range_in_vma(struct vm_area_struct *vma, #ifdef CONFIG_MMU pgprot_t vm_get_page_prot(unsigned long vm_flags); void vma_set_page_prot(struct vm_area_struct *vma); +void get_vma_name(struct vm_area_struct *vma, + const struct path **path, + const char **name, + const char **name_fmt); #else static inline pgprot_t vm_get_page_prot(unsigned long vm_flags) { diff --git a/kernel/panic.c b/kernel/panic.c index 753d12f4dc8f..2217e1d0ad44 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -77,6 +77,8 @@ EXPORT_SYMBOL_GPL(panic_timeout); #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 #define PANIC_PRINT_ALL_CPU_BT 0x00000040 #define PANIC_PRINT_BLOCKED_TASKS 0x00000080 +#define PANIC_PRINT_TASK_MAPS_INFO 0x00000100 + unsigned long panic_print; ATOMIC_NOTIFIER_HEAD(panic_notifier_list); @@ -208,6 +210,53 @@ void nmi_panic(struct pt_regs *regs, const char *msg) } EXPORT_SYMBOL(nmi_panic); +/* + * This function is called in panic proccess if the PANIC_PRINT_TASK_MAPS_INFO + * flag is specified in panic_print, which is helpful to debug panic issues due + * to an unhandled falut in user mode such as kill init. + */ +static void dump_task_maps_info(struct task_struct *tsk) +{ + struct pt_regs *user_ret = task_pt_regs(tsk); + struct mm_struct *mm = tsk->mm; + struct vm_area_struct *vma; + + if (!mm || !user_mode(user_ret)) + return; + + pr_info("Dump task %s:%d maps start\n", tsk->comm, task_pid_nr(tsk)); + mmap_read_lock(mm); + VMA_ITERATOR(vmi, mm, 0); + for_each_vma(vmi, vma) { + int flags = vma->vm_flags; + unsigned long long pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT; + const struct path *path; + const char *name_fmt, *name; + char name_buf[SZ_256]; + + get_vma_name(vma, &path, &name, &name_fmt); + if (path) { + name = d_path(path, name_buf, sizeof(name_buf)); + name = IS_ERR(name) ? "?" : name; + } else if (name || name_fmt) { + snprintf(name_buf, sizeof(name_buf), name_fmt ?: "%s", name); + name = name_buf; + } + + if (name) + pr_info("%08lx-%08lx %c%c%c%c %08llx %s\n", + vma->vm_start, vma->vm_end, + flags & VM_READ ? 'r' : '-', + flags & VM_WRITE ? 'w' : '-', + flags & VM_EXEC ? 'x' : '-', + flags & VM_MAYSHARE ? 's' : 'p', + pgoff, name); + + } + mmap_read_unlock(mm); + pr_info("Dump task %s:%d maps end\n", tsk->comm, task_pid_nr(tsk)); +} + static void panic_print_sys_info(bool console_flush) { if (console_flush) { @@ -233,6 +282,9 @@ static void panic_print_sys_info(bool console_flush) if (panic_print & PANIC_PRINT_BLOCKED_TASKS) show_state_filter(TASK_UNINTERRUPTIBLE); + + if (panic_print & PANIC_PRINT_TASK_MAPS_INFO) + dump_task_maps_info(current); } void check_panic_on_warn(const char *origin)
Currently, it's hard to debug panic issues caused by kill init, since there is no debug info from user mode in current panic msg such as the user_regs and maps info. This patch adds an option to dump task maps info in panic_print. - changes history: v3: https://lore.kernel.org/all/20240922095504.7182-1-qiwu.chen@transsion.com/ https://lore.kernel.org/all/20240922095504.7182-2-qiwu.chen@transsion.com/ v2: https://lore.kernel.org/all/20231110031553.33186-1-qiwu.chen@transsion.com/ v1: https://lore.kernel.org/all/20231110022720.GA3087@rlk/ Signed-off-by: qiwu.chen <qiwu.chen@transsion.com> --- .../admin-guide/kernel-parameters.txt | 1 + Documentation/admin-guide/sysctl/kernel.rst | 1 + fs/proc/task_mmu.c | 3 +- include/linux/mm.h | 4 ++ kernel/panic.c | 52 +++++++++++++++++++ 5 files changed, 60 insertions(+), 1 deletion(-)