On Fri, 2013-08-09 at 17:58 -0400, Vlad Yasevich wrote: > This patch fixes the following triggered bug ... > > [ 553.109742] kernel BUG at include/linux/skbuff.h:1813! > [ 553.109766] invalid opcode: 0000 [#1] SMP > [ 553.109789] Modules linked in: sctp libcrc32c rfcomm [...] > [ 553.110259] uinput i915 i2c_algo_bit drm_kms_helper e1000e drm ptp > pps_core i2c_core wmi video sunrpc > [ 553.110320] CPU: 0 PID: 1636 Comm: lt-test_1_to_1_ Not tainted > 3.11.0-rc3+ #2 > [ 553.110350] Hardware name: LENOVO 74597D6/74597D6, BIOS 6DET60WW > (3.10 ) 09/17/2009 > [ 553.110381] task: ffff88020a01dd40 ti: ffff880204ed0000 task.ti: > ffff880204ed0000 > [ 553.110411] RIP: 0010:[<ffffffffa0698017>] [<ffffffffa0698017>] > skb_orphan.part.9+0x4/0x6 [sctp] > [ 553.110459] RSP: 0018:ffff880204ed1bb8 EFLAGS: 00010286 > [ 553.110483] RAX: ffff8802086f5a40 RBX: ffff880204303300 RCX: > 0000000000000000 > [ 553.110487] RDX: ffff880204303c28 RSI: ffff8802086f5a40 RDI: > ffff880202158000 > [ 553.110487] RBP: ffff880204ed1bb8 R08: 0000000000000000 R09: > 0000000000000000 > [ 553.110487] R10: ffff88022f2d9a04 R11: ffff880233001600 R12: > 0000000000000000 > [ 553.110487] R13: ffff880204303c00 R14: ffff8802293d0000 R15: > ffff880202158000 > [ 553.110487] FS: 00007f31b31fe740(0000) GS:ffff88023bc00000(0000) > knlGS:0000000000000000 > [ 553.110487] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > [ 553.110487] CR2: 000000379980e3e0 CR3: 000000020d225000 CR4: > 00000000000407f0 > [ 553.110487] Stack: > [ 553.110487] ffff880204ed1ca8 ffffffffa068d7fc 0000000000000000 > 0000000000000000 > [ 553.110487] 0000000000000000 ffff8802293d0000 ffff880202158000 > ffffffff81cb7900 > [ 553.110487] 0000000000000000 0000400000001c68 ffff8802086f5a40 > 000000000000000f > [ 553.110487] Call Trace: > [ 553.110487] [<ffffffffa068d7fc>] sctp_sendmsg+0x6bc/0xc80 [sctp] > [ 553.110487] [<ffffffff8128f185>] ? sock_has_perm+0x75/0x90 > [ 553.110487] [<ffffffff815a3593>] inet_sendmsg+0x63/0xb0 > [ 553.110487] [<ffffffff8128f2b3>] ? selinux_socket_sendmsg+0x23/0x30 > [ 553.110487] [<ffffffff8151c5d6>] sock_sendmsg+0xa6/0xd0 > [ 553.110487] [<ffffffff81637b05>] ? _raw_spin_unlock_bh+0x15/0x20 > [ 553.110487] [<ffffffff8151cd38>] SYSC_sendto+0x128/0x180 > [ 553.110487] [<ffffffff8151ce6b>] ? SYSC_connect+0xdb/0x100 > [ 553.110487] [<ffffffffa0690031>] ? sctp_inet_listen+0x71/0x1f0 > [sctp] > [ 553.110487] [<ffffffff8151d35e>] SyS_sendto+0xe/0x10 > [ 553.110487] [<ffffffff81640202>] system_call_fastpath+0x16/0x1b > [ 553.110487] Code: e0 48 c7 c7 00 22 6a a0 e8 67 a3 f0 e0 48 c7 [...] > [ 553.110487] RIP [<ffffffffa0698017>] skb_orphan.part.9+0x4/0x6 > [sctp] > [ 553.110487] RSP <ffff880204ed1bb8> > [ 553.121578] ---[ end trace 46c20c5903ef5be2 ]--- > > When a SCTP data chunk is created, skb->sk is set by sctp_make_chunk(). > At a later time, sctp_sendmg() calls sctp_set_owner_w() which will attempt > to orphan the skb and correctly set the skb->sk. The skb_orphan call result > in the above crash since skb->sk was set the the destructor was not. > > The simple solution is to not set skb->sk for DATA chunks (since it > will be done later). Continue to do it for control chunks since > sctp needs the sk at a later timer and control chunks are not currently > accouted agains socket memory. > > Signed-off-by: Vlad Yasevich <vyasevich@xxxxxxxxx> > --- > net/sctp/sm_make_chunk.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c > index 780a2d4..4ff7803 100644 > --- a/net/sctp/sm_make_chunk.c > +++ b/net/sctp/sm_make_chunk.c > @@ -1385,8 +1385,12 @@ static struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc, > if (sctp_auth_send_cid(type, asoc)) > retval->auth = 1; > > - /* Set the skb to the belonging sock for accounting. */ > - skb->sk = sk; > + /* Set the skb to the belonging sock for accounting. Do not > + * do this for data chunks as that will be properly set > + * up later. > + */ > + if (type != SCTP_CID_DATA) > + skb->sk = sk; > > return retval; > nodata: This is ugly IMHO. Why not using a dummy destructor ? And I guess this patch is for net-next ? -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
