lkml.org 
[lkml]   [2018]   [Jul]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Date
Subject[PATCH mm] VFS: seq_file: ensure ->from is valid.

Previous patch ("VFS: simplify seq_file iteration code and interface")
removed code to set ->from to zero when ->count is zero, as ->from is
dead at that time. However it didn't ensure ->from was set properly
whenever ->count becomes non-zero.
This can only happen when ->show() is called. Of the three places it
is called one already has ->from set to zero. The other two are
fixed by setting from to zero after fully flushing the buffer (at which
point ->count will also be zero).

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: NeilBrown <neilb@suse.com>
---
fs/seq_file.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/seq_file.c b/fs/seq_file.c
index fd82585ab50f..1dea7a8a5255 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -220,6 +220,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
goto Done;
}
/* we need at least one record in buffer */
+ m->from = 0;
p = m->op->start(m, &m->index);
while (1) {
err = PTR_ERR(p);
--
2.14.0.rc0.dirty
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2018-07-07 05:30    [W:0.787 / U:0.124 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site