| Message ID | 1538429927-17834-4-git-send-email-rick.p.edgecombe@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KASLR feature to randomize each loadable module | expand |
For a previous version before making asked for corrections, this was: Reviewed-by: Kees Cook <keescook@chromium.org> On Mon, 2018-10-01 at 14:38 -0700, Rick Edgecombe wrote: > Add debugfs file "modfraginfo" for providing info on module space > fragmentation. > This can be used for determining if loadable module randomization is causing > any > problems for extreme module loading situations, like huge numbers of modules > or > extremely large modules. > > Sample output when KASLR is enabled and X86_64 is configured: > Largest free space: 897912 kB > Total free space: 1025424 kB > Allocations in backup area: 0 > > Sample output when just X86_64: > Largest free space: 897912 kB > Total free space: 1025424 kB > > Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> > --- > mm/vmalloc.c | 98 > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 97 insertions(+), 1 deletion(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 1954458..1b3c3da 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -18,6 +18,7 @@ > #include <linux/interrupt.h> > #include <linux/proc_fs.h> > #include <linux/seq_file.h> > +#include <linux/debugfs.h> > #include <linux/debugobjects.h> > #include <linux/kallsyms.h> > #include <linux/list.h> > @@ -36,6 +37,12 @@ > #include <asm/tlbflush.h> > #include <asm/shmparam.h> > > +#ifdef CONFIG_X86 > +#include <asm/page_types.h> > +#include <asm/setup.h> > +#include <asm/kaslr_modules.h> > +#endif > + > #include "internal.h" > > struct vfree_deferred { > @@ -2919,7 +2926,96 @@ static int __init proc_vmalloc_init(void) > proc_create_seq("vmallocinfo", 0400, NULL, &vmalloc_op); > return 0; > } > -module_init(proc_vmalloc_init); > +#elif defined(CONFIG_DEBUG_FS) > +static int __init proc_vmalloc_init(void) > +{ > + return 0; > +} > +#endif > > +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_RANDOMIZE_FINE_MODULE) > +static inline unsigned long is_in_backup(unsigned long addr) > +{ > + return addr >= MODULES_VADDR + get_modules_rand_len(); > +} > + > +static int modulefraginfo_debug_show(struct seq_file *m, void *v) > +{ > + unsigned long last_end = MODULES_VADDR; > + unsigned long total_free = 0; > + unsigned long largest_free = 0; > + unsigned long backup_cnt = 0; > + unsigned long gap; > + struct vmap_area *prev, *cur = NULL; > + > + spin_lock(&vmap_area_lock); > + > + if (!pvm_find_next_prev(MODULES_VADDR, &cur, &prev) || !cur) > + goto done; > + > + for (; cur->va_end <= MODULES_END; cur = list_next_entry(cur, list)) > { > + /* Don't count areas that are marked to be lazily freed */ > + if (!(cur->flags & VM_LAZY_FREE)) { > + if (kaslr_mod_randomize_each_module()) > + backup_cnt += is_in_backup(cur->va_start); > + gap = cur->va_start - last_end; > + if (gap > largest_free) > + largest_free = gap; > + total_free += gap; > + last_end = cur->va_end; > + } > + > + if (list_is_last(&cur->list, &vmap_area_list)) > + break; > + } > + > +done: > + gap = (MODULES_END - last_end); > + if (gap > largest_free) > + largest_free = gap; > + total_free += gap; > + > + spin_unlock(&vmap_area_lock); > + > + seq_printf(m, "\tLargest free space:\t%lu kB\n", largest_free / > 1024); > + seq_printf(m, "\t Total free space:\t%lu kB\n", total_free / 1024); > + > + if (kaslr_mod_randomize_each_module()) > + seq_printf(m, "Allocations in backup area:\t%lu\n", > backup_cnt); > + > + return 0; > +} > + > +static int proc_module_frag_debug_open(struct inode *inode, struct file > *file) > +{ > + return single_open(file, modulefraginfo_debug_show, NULL); > +} > + > +static const struct file_operations debug_module_frag_operations = { > + .open = proc_module_frag_debug_open, > + .read = seq_read, > + .llseek = seq_lseek, > + .release = single_release, > +}; > + > +static void __init debug_modfrag_init(void) > +{ > + debugfs_create_file("modfraginfo", 0400, NULL, NULL, > + &debug_module_frag_operations); > +} > +#elif defined(CONFIG_DEBUG_FS) || defined(CONFIG_PROC_FS) > +static void __init debug_modfrag_init(void) > +{ > +} > #endif > > +#if defined(CONFIG_DEBUG_FS) || defined(CONFIG_PROC_FS) > +static int __init info_vmalloc_init(void) > +{ > + proc_vmalloc_init(); > + debug_modfrag_init(); > + return 0; > +} > + > +module_init(info_vmalloc_init); > +#endif
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 1954458..1b3c3da 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -18,6 +18,7 @@ #include <linux/interrupt.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> +#include <linux/debugfs.h> #include <linux/debugobjects.h> #include <linux/kallsyms.h> #include <linux/list.h> @@ -36,6 +37,12 @@ #include <asm/tlbflush.h> #include <asm/shmparam.h> +#ifdef CONFIG_X86 +#include <asm/page_types.h> +#include <asm/setup.h> +#include <asm/kaslr_modules.h> +#endif + #include "internal.h" struct vfree_deferred { @@ -2919,7 +2926,96 @@ static int __init proc_vmalloc_init(void) proc_create_seq("vmallocinfo", 0400, NULL, &vmalloc_op); return 0; } -module_init(proc_vmalloc_init); +#elif defined(CONFIG_DEBUG_FS) +static int __init proc_vmalloc_init(void) +{ + return 0; +} +#endif +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_RANDOMIZE_FINE_MODULE) +static inline unsigned long is_in_backup(unsigned long addr) +{ + return addr >= MODULES_VADDR + get_modules_rand_len(); +} + +static int modulefraginfo_debug_show(struct seq_file *m, void *v) +{ + unsigned long last_end = MODULES_VADDR; + unsigned long total_free = 0; + unsigned long largest_free = 0; + unsigned long backup_cnt = 0; + unsigned long gap; + struct vmap_area *prev, *cur = NULL; + + spin_lock(&vmap_area_lock); + + if (!pvm_find_next_prev(MODULES_VADDR, &cur, &prev) || !cur) + goto done; + + for (; cur->va_end <= MODULES_END; cur = list_next_entry(cur, list)) { + /* Don't count areas that are marked to be lazily freed */ + if (!(cur->flags & VM_LAZY_FREE)) { + if (kaslr_mod_randomize_each_module()) + backup_cnt += is_in_backup(cur->va_start); + gap = cur->va_start - last_end; + if (gap > largest_free) + largest_free = gap; + total_free += gap; + last_end = cur->va_end; + } + + if (list_is_last(&cur->list, &vmap_area_list)) + break; + } + +done: + gap = (MODULES_END - last_end); + if (gap > largest_free) + largest_free = gap; + total_free += gap; + + spin_unlock(&vmap_area_lock); + + seq_printf(m, "\tLargest free space:\t%lu kB\n", largest_free / 1024); + seq_printf(m, "\t Total free space:\t%lu kB\n", total_free / 1024); + + if (kaslr_mod_randomize_each_module()) + seq_printf(m, "Allocations in backup area:\t%lu\n", backup_cnt); + + return 0; +} + +static int proc_module_frag_debug_open(struct inode *inode, struct file *file) +{ + return single_open(file, modulefraginfo_debug_show, NULL); +} + +static const struct file_operations debug_module_frag_operations = { + .open = proc_module_frag_debug_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static void __init debug_modfrag_init(void) +{ + debugfs_create_file("modfraginfo", 0400, NULL, NULL, + &debug_module_frag_operations); +} +#elif defined(CONFIG_DEBUG_FS) || defined(CONFIG_PROC_FS) +static void __init debug_modfrag_init(void) +{ +} #endif +#if defined(CONFIG_DEBUG_FS) || defined(CONFIG_PROC_FS) +static int __init info_vmalloc_init(void) +{ + proc_vmalloc_init(); + debug_modfrag_init(); + return 0; +} + +module_init(info_vmalloc_init); +#endif
Add debugfs file "modfraginfo" for providing info on module space fragmentation. This can be used for determining if loadable module randomization is causing any problems for extreme module loading situations, like huge numbers of modules or extremely large modules. Sample output when KASLR is enabled and X86_64 is configured: Largest free space: 897912 kB Total free space: 1025424 kB Allocations in backup area: 0 Sample output when just X86_64: Largest free space: 897912 kB Total free space: 1025424 kB Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> --- mm/vmalloc.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 97 insertions(+), 1 deletion(-)