[PATCH 12/24] task_diag: add a new group to get tasks memory mappings (v2)
From: Andrey Vagin
Date: Mon Jul 06 2015 - 04:53:47 EST
v2: Fixes from David Ahern
* Fix 8-byte alignment
* Change implementation of DIAG_VMA attribute:
This patch puts the filename into the task_diag_vma struct and
converts TASK_DIAG_VMA attribute into a series of task_diag_vma.
Now is there is a single TASK_DIAG_VMA attribute that is parsed
as:
| struct task_diag_vma | filename | ...
Cc: David Ahern <dsahern@xxxxxxxxx>
Signed-off-by: Andrey Vagin <avagin@xxxxxxxxxx>
---
include/uapi/linux/task_diag.h | 54 +++++++++
kernel/taskdiag.c | 255 ++++++++++++++++++++++++++++++++++++++++-
2 files changed, 306 insertions(+), 3 deletions(-)
diff --git a/include/uapi/linux/task_diag.h b/include/uapi/linux/task_diag.h
index c51380a..943d8d1 100644
--- a/include/uapi/linux/task_diag.h
+++ b/include/uapi/linux/task_diag.h
@@ -2,6 +2,7 @@
#define _LINUX_TASK_DIAG_H
#include <linux/types.h>
+#include <linux/netlink.h>
#include <linux/capability.h>
enum {
@@ -9,6 +10,7 @@ enum {
TASK_DIAG_BASE = 0,
TASK_DIAG_CRED,
TASK_DIAG_STAT,
+ TASK_DIAG_VMA,
/* other attributes */
TASK_DIAG_PID = 64, /* u32 */
@@ -20,6 +22,7 @@ enum {
#define TASK_DIAG_SHOW_BASE (1ULL << TASK_DIAG_BASE)
#define TASK_DIAG_SHOW_CRED (1ULL << TASK_DIAG_CRED)
#define TASK_DIAG_SHOW_STAT (1ULL << TASK_DIAG_STAT)
+#define TASK_DIAG_SHOW_VMA (1ULL << TASK_DIAG_VMA)
enum {
TASK_DIAG_RUNNING,
@@ -64,6 +67,57 @@ struct task_diag_creds {
__u32 fsgid;
};
+#define TASK_DIAG_VMA_F_READ (1ULL << 0)
+#define TASK_DIAG_VMA_F_WRITE (1ULL << 1)
+#define TASK_DIAG_VMA_F_EXEC (1ULL << 2)
+#define TASK_DIAG_VMA_F_SHARED (1ULL << 3)
+#define TASK_DIAG_VMA_F_MAYREAD (1ULL << 4)
+#define TASK_DIAG_VMA_F_MAYWRITE (1ULL << 5)
+#define TASK_DIAG_VMA_F_MAYEXEC (1ULL << 6)
+#define TASK_DIAG_VMA_F_MAYSHARE (1ULL << 7)
+#define TASK_DIAG_VMA_F_GROWSDOWN (1ULL << 8)
+#define TASK_DIAG_VMA_F_PFNMAP (1ULL << 9)
+#define TASK_DIAG_VMA_F_DENYWRITE (1ULL << 10)
+#define TASK_DIAG_VMA_F_MPX (1ULL << 11)
+#define TASK_DIAG_VMA_F_LOCKED (1ULL << 12)
+#define TASK_DIAG_VMA_F_IO (1ULL << 13)
+#define TASK_DIAG_VMA_F_SEQ_READ (1ULL << 14)
+#define TASK_DIAG_VMA_F_RAND_READ (1ULL << 15)
+#define TASK_DIAG_VMA_F_DONTCOPY (1ULL << 16)
+#define TASK_DIAG_VMA_F_DONTEXPAND (1ULL << 17)
+#define TASK_DIAG_VMA_F_ACCOUNT (1ULL << 18)
+#define TASK_DIAG_VMA_F_NORESERVE (1ULL << 19)
+#define TASK_DIAG_VMA_F_HUGETLB (1ULL << 20)
+#define TASK_DIAG_VMA_F_ARCH_1 (1ULL << 21)
+#define TASK_DIAG_VMA_F_DONTDUMP (1ULL << 22)
+#define TASK_DIAG_VMA_F_SOFTDIRTY (1ULL << 23)
+#define TASK_DIAG_VMA_F_MIXEDMAP (1ULL << 24)
+#define TASK_DIAG_VMA_F_HUGEPAGE (1ULL << 25)
+#define TASK_DIAG_VMA_F_NOHUGEPAGE (1ULL << 26)
+#define TASK_DIAG_VMA_F_MERGEABLE (1ULL << 27)
+
+/* task_diag_vma must be NLA_ALIGN'ed */
+struct task_diag_vma {
+ __u64 start, end;
+ __u64 vm_flags;
+ __u64 pgoff;
+ __u32 major;
+ __u32 minor;
+ __u64 inode;
+ __u32 generation;
+ __u16 vma_len;
+ __u16 name_off;
+ __u16 name_len;
+} __attribute__((__aligned__(NLA_ALIGNTO)));
+
+static inline char *task_diag_vma_name(struct task_diag_vma *vma)
+{
+ if (!vma->name_len)
+ return NULL;
+
+ return ((char *)vma) + vma->name_off;
+}
+
#define TASK_DIAG_DUMP_ALL 0
#define TASK_DIAG_DUMP_CHILDREN 1
diff --git a/kernel/taskdiag.c b/kernel/taskdiag.c
index a49ccab..c488c1b 100644
--- a/kernel/taskdiag.c
+++ b/kernel/taskdiag.c
@@ -8,7 +8,7 @@
#include <linux/sched.h>
#include <linux/taskstats.h>
-static size_t taskdiag_packet_size(u64 show_flags)
+static size_t taskdiag_packet_size(u64 show_flags, int n_vma)
{
size_t size;
@@ -23,6 +23,14 @@ static size_t taskdiag_packet_size(u64 show_flags)
if (show_flags & TASK_DIAG_SHOW_STAT)
size += nla_total_size(sizeof(struct taskstats));
+ if (show_flags & TASK_DIAG_SHOW_VMA && n_vma > 0) {
+ /*
+ * 128 is a schwag on average path length for maps; used to
+ * ballpark initial memory allocation for genl msg
+ */
+ size += nla_total_size(sizeof(struct task_diag_vma) * n_vma + 128);
+ }
+
return size;
}
@@ -150,12 +158,245 @@ static int fill_creds(struct task_struct *p, struct sk_buff *skb)
return 0;
}
+static u64 get_vma_flags(struct vm_area_struct *vma)
+{
+ u64 flags = 0;
+
+ static const u64 mnemonics[BITS_PER_LONG] = {
+ /*
+ * In case if we meet a flag we don't know about.
+ */
+ [0 ... (BITS_PER_LONG-1)] = 0,
+
+ [ilog2(VM_READ)] = TASK_DIAG_VMA_F_READ,
+ [ilog2(VM_WRITE)] = TASK_DIAG_VMA_F_WRITE,
+ [ilog2(VM_EXEC)] = TASK_DIAG_VMA_F_EXEC,
+ [ilog2(VM_SHARED)] = TASK_DIAG_VMA_F_SHARED,
+ [ilog2(VM_MAYREAD)] = TASK_DIAG_VMA_F_MAYREAD,
+ [ilog2(VM_MAYWRITE)] = TASK_DIAG_VMA_F_MAYWRITE,
+ [ilog2(VM_MAYEXEC)] = TASK_DIAG_VMA_F_MAYEXEC,
+ [ilog2(VM_MAYSHARE)] = TASK_DIAG_VMA_F_MAYSHARE,
+ [ilog2(VM_GROWSDOWN)] = TASK_DIAG_VMA_F_GROWSDOWN,
+ [ilog2(VM_PFNMAP)] = TASK_DIAG_VMA_F_PFNMAP,
+ [ilog2(VM_DENYWRITE)] = TASK_DIAG_VMA_F_DENYWRITE,
+#ifdef CONFIG_X86_INTEL_MPX
+ [ilog2(VM_MPX)] = TASK_DIAG_VMA_F_MPX,
+#endif
+ [ilog2(VM_LOCKED)] = TASK_DIAG_VMA_F_LOCKED,
+ [ilog2(VM_IO)] = TASK_DIAG_VMA_F_IO,
+ [ilog2(VM_SEQ_READ)] = TASK_DIAG_VMA_F_SEQ_READ,
+ [ilog2(VM_RAND_READ)] = TASK_DIAG_VMA_F_RAND_READ,
+ [ilog2(VM_DONTCOPY)] = TASK_DIAG_VMA_F_DONTCOPY,
+ [ilog2(VM_DONTEXPAND)] = TASK_DIAG_VMA_F_DONTEXPAND,
+ [ilog2(VM_ACCOUNT)] = TASK_DIAG_VMA_F_ACCOUNT,
+ [ilog2(VM_NORESERVE)] = TASK_DIAG_VMA_F_NORESERVE,
+ [ilog2(VM_HUGETLB)] = TASK_DIAG_VMA_F_HUGETLB,
+ [ilog2(VM_ARCH_1)] = TASK_DIAG_VMA_F_ARCH_1,
+ [ilog2(VM_DONTDUMP)] = TASK_DIAG_VMA_F_DONTDUMP,
+#ifdef CONFIG_MEM_SOFT_DIRTY
+ [ilog2(VM_SOFTDIRTY)] = TASK_DIAG_VMA_F_SOFTDIRTY,
+#endif
+ [ilog2(VM_MIXEDMAP)] = TASK_DIAG_VMA_F_MIXEDMAP,
+ [ilog2(VM_HUGEPAGE)] = TASK_DIAG_VMA_F_HUGEPAGE,
+ [ilog2(VM_NOHUGEPAGE)] = TASK_DIAG_VMA_F_NOHUGEPAGE,
+ [ilog2(VM_MERGEABLE)] = TASK_DIAG_VMA_F_MERGEABLE,
+ };
+ size_t i;
+
+ for (i = 0; i < BITS_PER_LONG; i++) {
+ if (vma->vm_flags & (1UL << i))
+ flags |= mnemonics[i];
+ }
+
+ return flags;
+}
+
+static int task_vma_num(struct mm_struct *mm)
+{
+ struct vm_area_struct *vma;
+ int n_vma = 0;
+
+ if (!mm || !atomic_inc_not_zero(&mm->mm_users))
+ return 0;
+
+ down_read(&mm->mmap_sem);
+ for (vma = mm->mmap; vma; vma = vma->vm_next, n_vma++)
+ ;
+
+ up_read(&mm->mmap_sem);
+ mmput(mm);
+
+ return n_vma;
+}
+
+/*
+ * use a tmp variable and copy to input arg to deal with
+ * alignment issues. diag_vma contains u64 elements which
+ * means extended load operations can be used and those can
+ * require 8-byte alignment (e.g., sparc)
+ */
+static void fill_diag_vma(struct vm_area_struct *vma,
+ struct task_diag_vma *diag_vma)
+{
+ struct task_diag_vma tmp;
+
+ /* We don't show the stack guard page in /proc/maps */
+ tmp.start = vma->vm_start;
+ if (stack_guard_page_start(vma, tmp.start))
+ tmp.start += PAGE_SIZE;
+
+ tmp.end = vma->vm_end;
+ if (stack_guard_page_end(vma, tmp.end))
+ tmp.end -= PAGE_SIZE;
+ tmp.vm_flags = get_vma_flags(vma);
+
+ if (vma->vm_file) {
+ struct inode *inode = file_inode(vma->vm_file);
+ dev_t dev;
+
+ dev = inode->i_sb->s_dev;
+ tmp.major = MAJOR(dev);
+ tmp.minor = MINOR(dev);
+ tmp.inode = inode->i_ino;
+ tmp.generation = inode->i_generation;
+ tmp.pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
+ } else {
+ tmp.major = 0;
+ tmp.minor = 0;
+ tmp.inode = 0;
+ tmp.generation = 0;
+ tmp.pgoff = 0;
+ }
+
+ memcpy(diag_vma, &tmp, sizeof(*diag_vma));
+}
+
+static const char *get_vma_name(struct vm_area_struct *vma, char *page)
+{
+ const char *name = NULL;
+
+ if (vma->vm_file) {
+ name = d_path(&vma->vm_file->f_path, page, PAGE_SIZE);
+ goto out;
+ }
+
+ if (vma->vm_ops && vma->vm_ops->name) {
+ name = vma->vm_ops->name(vma);
+ if (name)
+ goto out;
+ }
+
+ name = arch_vma_name(vma);
+
+out:
+ return name;
+}
+
+static int fill_vma(struct task_struct *p, struct sk_buff *skb,
+ struct netlink_callback *cb, bool *progress)
+{
+ struct vm_area_struct *vma;
+ struct mm_struct *mm;
+ struct nlattr *attr = NULL;
+ struct task_diag_vma *diag_vma;
+ unsigned long mark = 0;
+ char *page;
+ int i, rc = -EMSGSIZE;
+
+ if (cb)
+ mark = cb->args[3];
+
+ mm = p->mm;
+ if (!mm || !atomic_inc_not_zero(&mm->mm_users))
+ return 0;
+
+ page = (char *)__get_free_page(GFP_TEMPORARY);
+ if (!page) {
+ mmput(mm);
+ return -ENOMEM;
+ }
+
+ down_read(&mm->mmap_sem);
+ for (vma = mm->mmap; vma; vma = vma->vm_next, i++) {
+ unsigned char *b = skb_tail_pointer(skb);
+ const char *name;
+ void *pfile;
+
+
+ if (mark >= vma->vm_start)
+ continue;
+
+ /* setup pointer for next map */
+ if (attr == NULL) {
+ attr = nla_reserve(skb, TASK_DIAG_VMA, sizeof(*diag_vma));
+ if (!attr)
+ goto err;
+
+ diag_vma = nla_data(attr);
+ } else {
+ diag_vma = nla_reserve_nohdr(skb, sizeof(*diag_vma));
+
+ if (diag_vma == NULL) {
+ nlmsg_trim(skb, b);
+ goto out;
+ }
+ }
+
+ fill_diag_vma(vma, diag_vma);
+
+ name = get_vma_name(vma, page);
+ if (IS_ERR(name)) {
+ nlmsg_trim(skb, b);
+ rc = PTR_ERR(name);
+ goto out;
+ }
+
+ if (name) {
+ diag_vma->name_len = strlen(name) + 1;
+
+ /* reserves NLA_ALIGN(len) */
+ pfile = nla_reserve_nohdr(skb, diag_vma->name_len);
+ if (pfile == NULL) {
+ nlmsg_trim(skb, b);
+ goto out;
+ }
+ diag_vma->name_off = pfile - (void *) diag_vma;
+ memcpy(pfile, name, diag_vma->name_len);
+ } else {
+ diag_vma->name_len = 0;
+ diag_vma->name_off = 0;
+ }
+
+ mark = vma->vm_start;
+
+ diag_vma->vma_len = skb_tail_pointer(skb) - (unsigned char *) diag_vma;
+
+ *progress = true;
+ }
+
+ rc = 0;
+ mark = 0;
+out:
+ if (*progress)
+ attr->nla_len = skb_tail_pointer(skb) - (unsigned char *) attr;
+
+err:
+ up_read(&mm->mmap_sem);
+ mmput(mm);
+ free_page((unsigned long) page);
+ if (cb)
+ cb->args[3] = mark;
+
+ return rc;
+}
+
static int task_diag_fill(struct task_struct *tsk, struct sk_buff *skb,
u64 show_flags, u32 portid, u32 seq,
struct netlink_callback *cb)
{
void *reply;
int err = 0, i = 0, n = 0;
+ bool progress = false;
int flags = 0;
u32 pid;
@@ -198,13 +439,21 @@ static int task_diag_fill(struct task_struct *tsk, struct sk_buff *skb,
i++;
}
+ if (show_flags & TASK_DIAG_SHOW_VMA) {
+ if (i >= n)
+ err = fill_vma(tsk, skb, cb, &progress);
+ if (err)
+ goto err;
+ i++;
+ }
+
genlmsg_end(skb, reply);
if (cb)
cb->args[2] = 0;
return 0;
err:
- if (err == -EMSGSIZE && i != 0) {
+ if (err == -EMSGSIZE && (i > n || progress)) {
if (cb)
cb->args[2] = i;
genlmsg_end(skb, reply);
@@ -374,7 +623,7 @@ int taskdiag_doit(struct sk_buff *skb, struct genl_info *info)
return -EPERM;
}
- size = taskdiag_packet_size(req.show_flags);
+ size = taskdiag_packet_size(req.show_flags, task_vma_num(tsk->mm));
while (1) {
msg = genlmsg_new(size, GFP_KERNEL);
--
2.1.0
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