David Ahern 386fd5da40 tcp: Check daddr_cache before use in tracepoint ... Running perf in one window to capture tcp_retransmit_skb tracepoint: $ perf record -e tcp:tcp_retransmit_skb -a And causing a retransmission on an active TCP session (e.g., dropping packets in the receiver, changing MTU on the interface to 500 and back to 1500) triggers a panic: [ 58.543144] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 [ 58.545300] IP: perf_trace_tcp_retransmit_skb+0xd0/0x145 [ 58.546770] PGD 0 P4D 0 [ 58.547472] Oops: 0000 [#1] SMP [ 58.548328] Modules linked in: vrf [ 58.549262] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.0-rc4+ #26 [ 58.551004] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 58.554560] task: ffffffff81a0e540 task.stack: ffffffff81a00000 [ 58.555817] RIP: 0010:perf_trace_tcp_retransmit_skb+0xd0/0x145 [ 58.557137] RSP: 0018:ffff88003fc03d68 EFLAGS: 00010282 [ 58.558292] RAX: 0000000000000000 RBX: ffffe8ffffc0ec80 RCX: ffff880038543098 [ 58.559850] RDX: 0400000000000000 RSI: ffff88003fc03d70 RDI: ffff88003fc14b68 [ 58.561099] RBP: ffff88003fc03da8 R08: 0000000000000000 R09: ffffea0000d3224a [ 58.562005] R10: ffff88003fc03db8 R11: 0000000000000010 R12: ffff8800385428c0 [ 58.562930] R13: ffffe8ffffc0e478 R14: ffffffff81a93a40 R15: ffff88003d4f0c00 [ 58.563845] FS: 0000000000000000(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000 [ 58.564873] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 58.565613] CR2: 0000000000000008 CR3: 000000003d68f004 CR4: 00000000000606f0 [ 58.566538] Call Trace: [ 58.566865] <IRQ> [ 58.567140] __tcp_retransmit_skb+0x4ab/0x4c6 [ 58.567704] ? tcp_set_ca_state+0x22/0x3f [ 58.568231] tcp_retransmit_skb+0x14/0xa3 [ 58.568754] tcp_retransmit_timer+0x472/0x5e3 [ 58.569324] ? tcp_write_timer_handler+0x1e9/0x1e9 [ 58.569946] tcp_write_timer_handler+0x95/0x1e9 [ 58.570548] tcp_write_timer+0x2a/0x58 Check that daddr_cache is non-NULL before de-referencing. Fixes: e086101b15 ("tcp: add a tracepoint for tcp retransmission") Signed-off-by: David Ahern <dsahern@gmail.com> Acked-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2017-10-18 14:15:14 +01:00
..
acpi	ACPI / bus: Make ACPI_HANDLE() work for non-GPL code again	2017-09-19 22:42:31 +02:00
asm-generic	percpu: make this_cpu_generic_read() atomic w.r.t. interrupts	2017-09-26 07:37:33 -07:00
clocksource
crypto
drm	lib/interval_tree: fast overlap detection	2017-09-08 18:26:49 -07:00
dt-bindings	ARC: reset: remove the misleading v1 suffix all over	2017-09-18 13:02:03 +02:00
keys
kvm
linux	bpf: cpumap xdp_buff to skb conversion and allocation	2017-10-18 12:12:18 +01:00
math-emu
media	media updates for v4.14-rc1	2017-09-07 12:53:14 -07:00
memory
misc
net	inet: frags: Convert timers to use timer_setup()	2017-10-18 12:39:55 +01:00
pcmcia
ras
rdma	IB: Correct MR length field to be 64-bit	2017-09-25 11:47:23 -04:00
scsi	scsi: libiscsi: Remove iscsi_destroy_session	2017-10-02 22:23:21 -04:00
soc	ARM: SoC driver updates for v4.14	2017-09-10 20:40:00 -07:00
sound	sound fixes for 4.14-rc4	2017-10-05 10:39:29 -07:00
target
trace	tcp: Check daddr_cache before use in tracepoint	2017-10-18 14:15:14 +01:00
uapi	bpf: introduce new bpf cpu map type BPF_MAP_TYPE_CPUMAP	2017-10-18 12:12:18 +01:00
video
xen	xen, arm64: drop dummy lookup_address()	2017-09-19 09:25:05 -04:00