From 4d1ceea8516cd6adf21f6b75995e2a7d4f376f9b Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Mon, 30 Jan 2017 18:25:18 -0800 Subject: [PATCH] net: ethtool: convert large order kmalloc allocations to vzalloc under memory pressure 'ethtool -S' command may warn: [ 2374.385195] ethtool: page allocation failure: order:4, mode:0x242c0c0 [ 2374.405573] CPU: 12 PID: 40211 Comm: ethtool Not tainted [ 2374.423071] Call Trace: [ 2374.423076] [] dump_stack+0x4d/0x64 [ 2374.423080] [] warn_alloc_failed+0xeb/0x150 [ 2374.423082] [] ? __alloc_pages_direct_compact+0x43/0xf0 [ 2374.423084] [] __alloc_pages_nodemask+0x4dc/0xbf0 [ 2374.423091] [] ? cmd_exec+0x722/0xcd0 [mlx5_core] [ 2374.423095] [] alloc_pages_current+0x8c/0x110 [ 2374.423097] [] alloc_kmem_pages+0x19/0x90 [ 2374.423099] [] kmalloc_order_trace+0x2e/0xe0 [ 2374.423101] [] __kmalloc+0x204/0x220 [ 2374.423105] [] dev_ethtool+0xe4e/0x1f80 [ 2374.423106] [] ? dev_get_by_name_rcu+0x5e/0x80 [ 2374.423108] [] dev_ioctl+0x156/0x560 [ 2374.423111] [] ? mem_cgroup_commit_charge+0x78/0x3c0 [ 2374.423117] [] sock_do_ioctl+0x42/0x50 [ 2374.423119] [] sock_ioctl+0x1b3/0x250 [ 2374.423121] [] do_vfs_ioctl+0x92/0x580 [ 2374.423123] [] ? do_audit_syscall_entry+0x4b/0x70 [ 2374.423124] [] ? syscall_trace_enter_phase1+0xfc/0x120 [ 2374.423126] [] SyS_ioctl+0x79/0x90 [ 2374.423127] [] do_syscall_64+0x50/0xa0 [ 2374.423129] [] entry_SYSCALL64_slow_path+0x25/0x25 ~1160 mlx5 counters ~= order 4 allocation which is unlikely to succeed under memory pressure. Convert them to vzalloc() as ethtool_get_regs() does. Also take care of drivers without counters similar to commit 67ae7cf1eeda ("ethtool: Allow zero-length register dumps again") and reduce warn_on to warn_on_once. Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller --- net/core/ethtool.c | 39 ++++++++++++++++++++++----------------- 1 file changed, 22 insertions(+), 17 deletions(-) diff --git a/net/core/ethtool.c b/net/core/ethtool.c index 236a21e3c878..6b3eee0834a0 100644 --- a/net/core/ethtool.c +++ b/net/core/ethtool.c @@ -1817,11 +1817,13 @@ static int ethtool_get_strings(struct net_device *dev, void __user *useraddr) ret = __ethtool_get_sset_count(dev, gstrings.string_set); if (ret < 0) return ret; + if (ret > S32_MAX / ETH_GSTRING_LEN) + return -ENOMEM; + WARN_ON_ONCE(!ret); gstrings.len = ret; - - data = kcalloc(gstrings.len, ETH_GSTRING_LEN, GFP_USER); - if (!data) + data = vzalloc(gstrings.len * ETH_GSTRING_LEN); + if (gstrings.len && !data) return -ENOMEM; __ethtool_get_strings(dev, gstrings.string_set, data); @@ -1830,12 +1832,13 @@ static int ethtool_get_strings(struct net_device *dev, void __user *useraddr) if (copy_to_user(useraddr, &gstrings, sizeof(gstrings))) goto out; useraddr += sizeof(gstrings); - if (copy_to_user(useraddr, data, gstrings.len * ETH_GSTRING_LEN)) + if (gstrings.len && + copy_to_user(useraddr, data, gstrings.len * ETH_GSTRING_LEN)) goto out; ret = 0; out: - kfree(data); + vfree(data); return ret; } @@ -1912,14 +1915,15 @@ static int ethtool_get_stats(struct net_device *dev, void __user *useraddr) n_stats = ops->get_sset_count(dev, ETH_SS_STATS); if (n_stats < 0) return n_stats; - WARN_ON(n_stats == 0); - + if (n_stats > S32_MAX / sizeof(u64)) + return -ENOMEM; + WARN_ON_ONCE(!n_stats); if (copy_from_user(&stats, useraddr, sizeof(stats))) return -EFAULT; stats.n_stats = n_stats; - data = kmalloc(n_stats * sizeof(u64), GFP_USER); - if (!data) + data = vzalloc(n_stats * sizeof(u64)); + if (n_stats && !data) return -ENOMEM; ops->get_ethtool_stats(dev, &stats, data); @@ -1928,12 +1932,12 @@ static int ethtool_get_stats(struct net_device *dev, void __user *useraddr) if (copy_to_user(useraddr, &stats, sizeof(stats))) goto out; useraddr += sizeof(stats); - if (copy_to_user(useraddr, data, stats.n_stats * sizeof(u64))) + if (n_stats && copy_to_user(useraddr, data, n_stats * sizeof(u64))) goto out; ret = 0; out: - kfree(data); + vfree(data); return ret; } @@ -1948,17 +1952,18 @@ static int ethtool_get_phy_stats(struct net_device *dev, void __user *useraddr) return -EOPNOTSUPP; n_stats = phy_get_sset_count(phydev); - if (n_stats < 0) return n_stats; - WARN_ON(n_stats == 0); + if (n_stats > S32_MAX / sizeof(u64)) + return -ENOMEM; + WARN_ON_ONCE(!n_stats); if (copy_from_user(&stats, useraddr, sizeof(stats))) return -EFAULT; stats.n_stats = n_stats; - data = kmalloc_array(n_stats, sizeof(u64), GFP_USER); - if (!data) + data = vzalloc(n_stats * sizeof(u64)); + if (n_stats && !data) return -ENOMEM; mutex_lock(&phydev->lock); @@ -1969,12 +1974,12 @@ static int ethtool_get_phy_stats(struct net_device *dev, void __user *useraddr) if (copy_to_user(useraddr, &stats, sizeof(stats))) goto out; useraddr += sizeof(stats); - if (copy_to_user(useraddr, data, stats.n_stats * sizeof(u64))) + if (n_stats && copy_to_user(useraddr, data, n_stats * sizeof(u64))) goto out; ret = 0; out: - kfree(data); + vfree(data); return ret; } -- 2.20.1