* [PATCH 0/6] netdev: seq_file .next functions should increase position index
@ 2020-01-23 7:11 Vasily Averin
2020-01-24 10:42 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Vasily Averin @ 2020-01-23 7:11 UTC (permalink / raw)
To: David S. Miller; +Cc: Vishal Kulkarni, netdev
In Aug 2018 NeilBrown noticed
commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
"Some ->next functions do not increment *pos when they return NULL...
Note that such ->next functions are buggy and should be fixed.
A simple demonstration is
dd if=/proc/swaps bs=1000 skip=1
Choose any block size larger than the size of /proc/swaps. This will
always show the whole last line of /proc/swaps"
Described problem is still actual. If you make lseek into middle of last output line
following read will output end of last line and whole last line once again.
$ dd if=/proc/swaps bs=1 # usual output
Filename Type Size Used Priority
/dev/dm-0 partition 4194812 97536 -2
104+0 records in
104+0 records out
104 bytes copied
$ dd if=/proc/swaps bs=40 skip=1 # last line was generated twice
dd: /proc/swaps: cannot skip to specified offset
v/dm-0 partition 4194812 97536 -2
/dev/dm-0 partition 4194812 97536 -2
3+1 records in
3+1 records out
131 bytes copied
There are lot of other affected files, I've found 30+ including
/proc/net/ip_tables_matches and /proc/sysvipc/*
This patch-set fixes files related to netdev@
https://bugzilla.kernel.org/show_bug.cgi?id=206283
Vasily Averin (6):
seq_tab_next() should increase position index
l2t_seq_next should increase position index
vcc_seq_next should increase position index
neigh_stat_seq_next() should increase position index
rt_cpu_seq_next should increase position index
ipv6_route_seq_next should increase position index
drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c | 3 +--
drivers/net/ethernet/chelsio/cxgb4/l2t.c | 3 +--
net/atm/proc.c | 3 +--
net/core/neighbour.c | 1 +
net/ipv4/route.c | 1 +
net/ipv6/ip6_fib.c | 7 ++-----
6 files changed, 7 insertions(+), 11 deletions(-)
--
1.8.3.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH 0/6] netdev: seq_file .next functions should increase position index
2020-01-23 7:11 [PATCH 0/6] netdev: seq_file .next functions should increase position index Vasily Averin
@ 2020-01-24 10:42 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2020-01-24 10:42 UTC (permalink / raw)
To: vvs; +Cc: vishal, netdev
From: Vasily Averin <vvs@virtuozzo.com>
Date: Thu, 23 Jan 2020 10:11:01 +0300
> In Aug 2018 NeilBrown noticed
> commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
> "Some ->next functions do not increment *pos when they return NULL...
> Note that such ->next functions are buggy and should be fixed.
> A simple demonstration is
...
> There are lot of other affected files, I've found 30+ including
> /proc/net/ip_tables_matches and /proc/sysvipc/*
>
> This patch-set fixes files related to netdev@
>
> https://bugzilla.kernel.org/show_bug.cgi?id=206283
Series applied, thank you.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2020-01-23 7:11 [PATCH 0/6] netdev: seq_file .next functions should increase position index Vasily Averin
2020-01-24 10:42 ` David Miller
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