From: Dan Carpenter <dan.carpenter@oracle.com> To: Andrew Morton <akpm@linux-foundation.org>, Shaohua Li <shli@kernel.org> Cc: Huang Ying <ying.huang@intel.com>, Daniel Jordan <daniel.m.jordan@oracle.com>, Dave Hansen <dave.hansen@linux.intel.com>, Stephen Rothwell <sfr@canb.auug.org.au>, Omar Sandoval <osandov@fb.com>, Tejun Heo <tj@kernel.org>, Andi Kleen <ak@linux.intel.com>, linux-mm@kvack.org, kernel-janitors@vger.kernel.org Subject: [PATCH] mm, swap: Potential NULL dereference in get_swap_page_of_type() Date: Fri, 11 Jan 2019 09:59:19 +0000 [thread overview] Message-ID: <20190111095919.GA1757@kadam> (raw) Smatch complains that the NULL checks on "si" aren't consistent. This seems like a real bug because we have not ensured that the type is valid and so "si" can be NULL. Fixes: ec8acf20afb8 ("swap: add per-partition lock for swapfile") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- mm/swapfile.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index f0edf7244256..21e92c757205 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1048,9 +1048,12 @@ swp_entry_t get_swap_page_of_type(int type) struct swap_info_struct *si; pgoff_t offset; + if (type >= nr_swapfiles) + goto fail; + si = swap_info[type]; spin_lock(&si->lock); - if (si && (si->flags & SWP_WRITEOK)) { + if (si->flags & SWP_WRITEOK) { atomic_long_dec(&nr_swap_pages); /* This is called for allocating swap entry, not cache */ offset = scan_swap_map(si, 1); @@ -1061,6 +1064,7 @@ swp_entry_t get_swap_page_of_type(int type) atomic_long_inc(&nr_swap_pages); } spin_unlock(&si->lock); +fail: return (swp_entry_t) {0}; } -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com> To: Andrew Morton <akpm@linux-foundation.org>, Shaohua Li <shli@kernel.org> Cc: Huang Ying <ying.huang@intel.com>, Daniel Jordan <daniel.m.jordan@oracle.com>, Dave Hansen <dave.hansen@linux.intel.com>, Stephen Rothwell <sfr@canb.auug.org.au>, Omar Sandoval <osandov@fb.com>, Tejun Heo <tj@kernel.org>, Andi Kleen <ak@linux.intel.com>, linux-mm@kvack.org, kernel-janitors@vger.kernel.org Subject: [PATCH] mm, swap: Potential NULL dereference in get_swap_page_of_type() Date: Fri, 11 Jan 2019 12:59:19 +0300 [thread overview] Message-ID: <20190111095919.GA1757@kadam> (raw) Smatch complains that the NULL checks on "si" aren't consistent. This seems like a real bug because we have not ensured that the type is valid and so "si" can be NULL. Fixes: ec8acf20afb8 ("swap: add per-partition lock for swapfile") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- mm/swapfile.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index f0edf7244256..21e92c757205 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1048,9 +1048,12 @@ swp_entry_t get_swap_page_of_type(int type) struct swap_info_struct *si; pgoff_t offset; + if (type >= nr_swapfiles) + goto fail; + si = swap_info[type]; spin_lock(&si->lock); - if (si && (si->flags & SWP_WRITEOK)) { + if (si->flags & SWP_WRITEOK) { atomic_long_dec(&nr_swap_pages); /* This is called for allocating swap entry, not cache */ offset = scan_swap_map(si, 1); @@ -1061,6 +1064,7 @@ swp_entry_t get_swap_page_of_type(int type) atomic_long_inc(&nr_swap_pages); } spin_unlock(&si->lock); +fail: return (swp_entry_t) {0}; } -- 2.17.1
next reply other threads:[~2019-01-11 9:59 UTC|newest] Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-11 9:59 Dan Carpenter [this message] 2019-01-11 9:59 ` [PATCH] mm, swap: Potential NULL dereference in get_swap_page_of_type() Dan Carpenter 2019-01-11 17:41 ` Daniel Jordan 2019-01-11 17:41 ` Daniel Jordan 2019-01-11 23:20 ` Andrea Parri 2019-01-11 23:20 ` Andrea Parri 2019-01-14 22:25 ` Daniel Jordan 2019-01-14 22:25 ` Daniel Jordan 2019-01-15 0:23 ` [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL derefs Daniel Jordan 2019-01-15 0:23 ` Daniel Jordan 2019-01-15 1:17 ` Andrea Parri 2019-01-15 1:17 ` Andrea Parri 2019-01-30 6:26 ` Andrew Morton 2019-01-30 6:26 ` Andrew Morton 2019-01-31 1:52 ` Daniel Jordan 2019-01-31 1:52 ` Daniel Jordan 2019-01-31 2:44 ` [PATCH v2] mm, swap: bounds check swap_info array " Daniel Jordan 2019-01-31 2:44 ` Daniel Jordan 2019-01-31 2:48 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL d Huang, Ying 2019-01-31 2:48 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL derefs) Huang, Ying 2019-01-31 20:46 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NU Andrew Morton 2019-01-31 20:46 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL derefs) Andrew Morton 2019-02-02 7:14 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NU Huang, Ying 2019-02-02 7:14 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL derefs) Huang, Ying 2019-02-04 21:37 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NU Hugh Dickins 2019-02-04 21:37 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL derefs) Hugh Dickins 2019-02-04 22:26 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NU Matthew Wilcox 2019-02-04 22:26 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL derefs) Matthew Wilcox 2019-02-06 0:14 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NU Huang, Ying 2019-02-06 0:14 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL derefs) Huang, Ying 2019-02-06 0:36 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NU Hugh Dickins 2019-02-06 0:36 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL derefs) Hugh Dickins 2019-02-06 0:58 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NU Huang, Ying 2019-02-06 0:58 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL derefs) Huang, Ying 2019-02-08 0:28 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NU Andrea Parri 2019-02-08 0:28 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL derefs) Andrea Parri 2019-02-11 1:02 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NU Huang, Ying 2019-02-11 1:02 ` About swapoff race patch (was Re: [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL derefs) Huang, Ying 2019-01-30 7:28 ` [PATCH] mm, swap: bounds check swap_info accesses to avoid NULL derefs Dan Carpenter 2019-01-30 7:28 ` Dan Carpenter 2019-01-31 1:55 ` Daniel Jordan 2019-01-31 1:55 ` Daniel Jordan 2019-01-30 9:13 ` Peter Zijlstra 2019-01-30 9:13 ` Peter Zijlstra 2019-01-31 2:00 ` Daniel Jordan 2019-01-31 2:00 ` Daniel Jordan 2019-01-15 0:28 ` [PATCH] mm, swap: Potential NULL dereference in get_swap_page_of_type() Andrea Parri 2019-01-15 0:28 ` Andrea Parri 2019-01-14 2:12 ` Huang, Ying 2019-01-14 2:12 ` Huang, Ying 2019-01-14 2:12 ` Huang, Ying 2019-01-14 8:43 ` Dan Carpenter 2019-01-14 8:43 ` Dan Carpenter 2019-01-14 23:40 ` Daniel Jordan 2019-01-14 23:40 ` Daniel Jordan
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