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proc: fix vma display mismatch between /proc/pid/{maps,smaps}

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Commit 4752c36978 aka
"maps4: simplify interdependence of maps and smaps" broke /proc/pid/smaps,
causing it to display some vmas twice and other vmas not at all.  For example:

    grep .- /proc/1/smaps >/tmp/smaps; diff /proc/1/maps /tmp/smaps

    1  25d24
    2  < 7fd7e23aa000-7fd7e23ac000 rw-p 7fd7e23aa000 00:00 0
    3  28a28
    4  > ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0  [vsyscall]

The bug has something to do with setting m->version before all the
seq_printf's have been performed.  show_map was doing this correctly,
but show_smap was doing this in the middle of its seq_printf sequence.
This patch arranges things so that the setting of m->version in show_smap
is also done at the end of its seq_printf sequence.

Testing: in addition to the above grep test, for each process I summed
up the 'Rss' fields of /proc/pid/smaps and compared that to the 'VmRSS'
field of /proc/pid/status.  All matched except for Xorg (which has a
/dev/mem mapping which Rss accounts for but VmRSS does not).  This result
gives us some confidence that neither /proc/pid/maps nor /proc/pid/smaps
are any longer skipping or double-counting vmas.

Signed-off-by: Joe Korty <joe.korty@ccur.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
This commit is contained in:
Joe Korty 2008-10-16 15:27:09 +04:00 committed by Alexey Dobriyan
parent 2515ddc6db
commit 7c88db0cb5
1 changed files with 16 additions and 9 deletions
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25
fs/proc/task_mmu.c
View File

@ -198,11 +198,8 @@ static int do_maps_open(struct inode *inode, struct file *file,
return ret;
}
static int show_map(struct seq_file *m, void *v)
static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
{
struct proc_maps_private *priv = m->private;
struct task_struct *task = priv->task;
struct vm_area_struct *vma = v;
struct mm_struct *mm = vma->vm_mm;
struct file *file = vma->vm_file;
int flags = vma->vm_flags;
@ -254,6 +251,15 @@ static int show_map(struct seq_file *m, void *v)
}
}
seq_putc(m, '\n');
}
static int show_map(struct seq_file *m, void *v)
{
struct vm_area_struct *vma = v;
struct proc_maps_private *priv = m->private;
struct task_struct *task = priv->task;
show_map_vma(m, vma);
if (m->count < m->size) /* vma is copied successfully */
m->version = (vma != get_gate_vma(task))? vma->vm_start: 0;
@ -364,9 +370,10 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
static int show_smap(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
struct task_struct *task = priv->task;
struct vm_area_struct *vma = v;
struct mem_size_stats mss;
int ret;
struct mm_walk smaps_walk = {
.pmd_entry = smaps_pte_range,
.mm = vma->vm_mm,
@ -378,9 +385,7 @@ static int show_smap(struct seq_file *m, void *v)
if (vma->vm_mm && !is_vm_hugetlb_page(vma))
walk_page_range(vma->vm_start, vma->vm_end, &smaps_walk);
ret = show_map(m, v);
if (ret)
return ret;
show_map_vma(m, vma);
seq_printf(m,
"Size: %8lu kB\n"
@ -402,7 +407,9 @@ static int show_smap(struct seq_file *m, void *v)
mss.referenced >> 10,
mss.swap >> 10);
return ret;
if (m->count < m->size) /* vma is copied successfully */
m->version = (vma != get_gate_vma(task)) ? vma->vm_start : 0;
return 0;
}
static const struct seq_operations proc_pid_smaps_op = {