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| author | Thomas Tuttle <ttuttle@google.com> | 2008-06-05 22:46:31 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-06-06 11:29:11 -0700 |
| commit | aae8679b0ebcaa92f99c1c3cb0cd651594a43915 (patch) | |
| tree | 26d761d3c4cca09b58538a576948a7ba720f7d5a /fs/proc | |
| parent | d1ee2971f5bd8a16bc5ecfe1b00e14b4fe407c4f (diff) | |
| download | kernel_samsung_aries-aae8679b0ebcaa92f99c1c3cb0cd651594a43915.zip kernel_samsung_aries-aae8679b0ebcaa92f99c1c3cb0cd651594a43915.tar.gz kernel_samsung_aries-aae8679b0ebcaa92f99c1c3cb0cd651594a43915.tar.bz2 | |
pagemap: fix bug in add_to_pagemap, require aligned-length reads of /proc/pid/pagemap
Fix a bug in add_to_pagemap. Previously, since pm->out was a char *,
put_user was only copying 1 byte of every PFN, resulting in the top 7
bytes of each PFN not being copied. By requiring that reads be a multiple
of 8 bytes, I can make pm->out and pm->end u64*s instead of char*s, which
makes put_user work properly, and also simplifies the logic in
add_to_pagemap a bit.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Thomas Tuttle <ttuttle@google.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc')
| -rw-r--r-- | fs/proc/task_mmu.c | 28 |
1 files changed, 9 insertions, 19 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 88717c0..1740362 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -496,7 +496,7 @@ const struct file_operations proc_clear_refs_operations = { }; struct pagemapread { - char __user *out, *end; + u64 __user *out, *end; }; #define PM_ENTRY_BYTES sizeof(u64) @@ -519,21 +519,11 @@ struct pagemapread { static int add_to_pagemap(unsigned long addr, u64 pfn, struct pagemapread *pm) { - /* - * Make sure there's room in the buffer for an - * entire entry. Otherwise, only copy part of - * the pfn. - */ - if (pm->out + PM_ENTRY_BYTES >= pm->end) { - if (copy_to_user(pm->out, &pfn, pm->end - pm->out)) - return -EFAULT; - pm->out = pm->end; - return PM_END_OF_BUFFER; - } - if (put_user(pfn, pm->out)) return -EFAULT; - pm->out += PM_ENTRY_BYTES; + pm->out++; + if (pm->out >= pm->end) + return PM_END_OF_BUFFER; return 0; } @@ -634,7 +624,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, ret = -EINVAL; /* file position must be aligned */ - if (*ppos % PM_ENTRY_BYTES) + if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES)) goto out_task; ret = 0; @@ -664,8 +654,8 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, goto out_pages; } - pm.out = buf; - pm.end = buf + count; + pm.out = (u64 *)buf; + pm.end = (u64 *)(buf + count); if (!ptrace_may_attach(task)) { ret = -EIO; @@ -690,9 +680,9 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, if (ret == PM_END_OF_BUFFER) ret = 0; /* don't need mmap_sem for these, but this looks cleaner */ - *ppos += pm.out - buf; + *ppos += (char *)pm.out - buf; if (!ret) - ret = pm.out - buf; + ret = (char *)pm.out - buf; } out_pages: |