diff options
| author | Han Pingtian <hanpt@linux.vnet.ibm.com> | 2014-08-28 19:34:12 +0100 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2014-09-26 11:51:50 +0200 |
| commit | 73210d0adac4c6f283eb825e85febdc12dbd3e36 (patch) | |
| tree | 65e110487ea501cff2e1842e2547f69fd535f12d /mm | |
| parent | 3ddc614ca27c84a91d3b51ab57e50c68fdf4889b (diff) | |
mm: prevent setting of a value less than 0 to min_free_kbytes
commit da8c757b080ee84f219fa2368cb5dd23ac304fc0 upstream.
If echo -1 > /proc/vm/sys/min_free_kbytes, the system will hang. Changing
proc_dointvec() to proc_dointvec_minmax() in the
min_free_kbytes_sysctl_handler() can prevent this to happen.
mhocko said:
: You can still do echo $BIG_VALUE > /proc/vm/sys/min_free_kbytes and make
: your machine unusable but I agree that proc_dointvec_minmax is more
: suitable here as we already have:
:
: .proc_handler = min_free_kbytes_sysctl_handler,
: .extra1 = &zero,
:
: It used to work properly but then 6fce56ec91b5 ("sysctl: Remove references
: to ctl_name and strategy from the generic sysctl table") has removed
: sysctl_intvec strategy and so extra1 is ignored.
Signed-off-by: Han Pingtian <hanpt@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page_alloc.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a280f772bc66..95f20173abba 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5734,7 +5734,12 @@ module_init(init_per_zone_wmark_min) int min_free_kbytes_sysctl_handler(ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos) { - proc_dointvec(table, write, buffer, length, ppos); + int rc; + + rc = proc_dointvec_minmax(table, write, buffer, length, ppos); + if (rc) + return rc; + if (write) { user_min_free_kbytes = min_free_kbytes; setup_per_zone_wmarks(); |