2.6.27-stable review patch. If anyone has any objections, please let us know. ------------------ From: Herbert Xu [ Upstream commit 905db44087855e3c1709f538ecdc22fd149cadd8 ] As the mmap handler gets called under mmap_sem, and we may grab mmap_sem elsewhere under the socket lock to access user data, we should avoid grabbing the socket lock in the mmap handler. Since the only thing we care about in the mmap handler is for pg_vec* to be invariant, i.e., to exclude packet_set_ring, we can achieve this by simply using a new mutex. Signed-off-by: Herbert Xu Tested-by: Martin MOKREJŠ Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/packet/af_packet.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -77,6 +77,7 @@ #include #include #include +#include #ifdef CONFIG_INET #include @@ -175,6 +176,7 @@ struct packet_sock { #endif struct packet_type prot_hook; spinlock_t bind_lock; + struct mutex pg_vec_lock; unsigned int running:1, /* prot_hook is attached*/ auxdata:1, origdev:1; @@ -1068,6 +1070,7 @@ static int packet_create(struct net *net */ spin_lock_init(&po->bind_lock); + mutex_init(&po->pg_vec_lock); po->prot_hook.func = packet_rcv; if (sock->type == SOCK_PACKET) @@ -1863,6 +1866,7 @@ static int packet_set_ring(struct sock * synchronize_net(); err = -EBUSY; + mutex_lock(&po->pg_vec_lock); if (closing || atomic_read(&po->mapped) == 0) { err = 0; #define XC(a, b) ({ __typeof__ ((a)) __t; __t = (a); (a) = (b); __t; }) @@ -1884,6 +1888,7 @@ static int packet_set_ring(struct sock * if (atomic_read(&po->mapped)) printk(KERN_DEBUG "packet_mmap: vma is busy: %d\n", atomic_read(&po->mapped)); } + mutex_unlock(&po->pg_vec_lock); spin_lock(&po->bind_lock); if (was_running && !po->running) { @@ -1916,7 +1921,7 @@ static int packet_mmap(struct file *file size = vma->vm_end - vma->vm_start; - lock_sock(sk); + mutex_lock(&po->pg_vec_lock); if (po->pg_vec == NULL) goto out; if (size != po->pg_vec_len*po->pg_vec_pages*PAGE_SIZE) @@ -1939,7 +1944,7 @@ static int packet_mmap(struct file *file err = 0; out: - release_sock(sk); + mutex_unlock(&po->pg_vec_lock); return err; } #endif -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/