Arend,
I just wanted to double check that you have received my second patch
as I'm beginning to be slightly worried that your spam filters are
blocking my stack traces.
- Alexander Coffin
On Mon, Aug 8, 2022 at 10:50 AM Alexander Coffin
<alex.coffin@xxxxxxxxxxxx> wrote:
>
> > ret = brcmf_proto_tx_queue_data(drvr, ifp->ifidx, skb);
>
> may be schedule, and then complete before the line
>
> > ndev->stats.tx_bytes += skb->len;
>
> [ 46.912801] ==================================================================
> [ 46.920552] BUG: KASAN: use-after-free in brcmf_netdev_start_xmit+0x718/0x8c8 [brcmfmac]
> [ 46.928673] Read of size 4 at addr ffffff803f5882e8 by task systemd-resolve/328
> [ 46.935991]
> [ 46.937514] CPU: 1 PID: 328 Comm: systemd-resolve Tainted: G O 5.4.199-[REDACTED] #1
> [ 46.947255] Hardware name: [REDACTED]
> [ 46.954568] Call trace:
> [ 46.957037] dump_backtrace+0x0/0x2b8
> [ 46.960719] show_stack+0x24/0x30
> [ 46.964052] dump_stack+0x128/0x194
> [ 46.967557] print_address_description.isra.0+0x64/0x380
> [ 46.972877] __kasan_report+0x1d4/0x240
> [ 46.976723] kasan_report+0xc/0x18
> [ 46.980138] __asan_report_load4_noabort+0x18/0x20
> [ 46.985027] brcmf_netdev_start_xmit+0x718/0x8c8 [brcmfmac]
> [ 46.990613] dev_hard_start_xmit+0x1bc/0xda0
> [ 46.994894] sch_direct_xmit+0x198/0xd08
> [ 46.998827] __qdisc_run+0x37c/0x1dc0
> [ 47.002500] __dev_queue_xmit+0x1528/0x21f8
> [ 47.006692] dev_queue_xmit+0x24/0x30
> [ 47.010366] neigh_resolve_output+0x37c/0x678
> [ 47.014734] ip_finish_output2+0x598/0x2458
> [ 47.018927] __ip_finish_output+0x300/0x730
> [ 47.023118] ip_output+0x2e0/0x430
> [ 47.026530] ip_local_out+0x90/0x140
> [ 47.030117] igmpv3_sendpack+0x14c/0x228
> [ 47.034049] igmpv3_send_cr+0x384/0x6b8
> [ 47.037895] igmp_ifc_timer_expire+0x4c/0x118
> [ 47.042262] call_timer_fn+0x1cc/0xbe8
> [ 47.046021] __run_timers+0x4d8/0xb28
> [ 47.049693] run_timer_softirq+0x24/0x40
> [ 47.053626] __do_softirq+0x2c0/0x117c
> [ 47.057387] irq_exit+0x2dc/0x388
> [ 47.060715] __handle_domain_irq+0xb4/0x158
> [ 47.064908] gic_handle_irq+0x58/0xb0
> [ 47.068581] el0_irq_naked+0x50/0x5c
> [ 47.072162]
> [ 47.073665] Allocated by task 328:
> [ 47.077083] save_stack+0x24/0xb0
> [ 47.080410] __kasan_kmalloc.isra.0+0xc0/0xe0
> [ 47.084776] kasan_slab_alloc+0x14/0x20
> [ 47.088622] kmem_cache_alloc+0x15c/0x468
> [ 47.092643] __alloc_skb+0xa4/0x498
> [ 47.096142] igmpv3_newpack+0x158/0xd78
> [ 47.099987] add_grhead+0x210/0x288
> [ 47.103485] add_grec+0x6b0/0xb70
> [ 47.106811] igmpv3_send_cr+0x2e0/0x6b8
> [ 47.110657] igmp_ifc_timer_expire+0x4c/0x118
> [ 47.115027] call_timer_fn+0x1cc/0xbe8
> [ 47.118785] __run_timers+0x4d8/0xb28
> [ 47.122457] run_timer_softirq+0x24/0x40
> [ 47.126389] __do_softirq+0x2c0/0x117c
> [ 47.130142]
> [ 47.131643] Freed by task 180:
> [ 47.134712] save_stack+0x24/0xb0
> [ 47.138041] __kasan_slab_free+0x108/0x180
> [ 47.142146] kasan_slab_free+0x10/0x18
> [ 47.145904] slab_free_freelist_hook+0xa4/0x1b0
> [ 47.150444] kmem_cache_free+0x8c/0x528
> [ 47.154292] kfree_skbmem+0x94/0x108
> [ 47.157880] consume_skb+0x10c/0x5a8
> [ 47.161466] __dev_kfree_skb_any+0x88/0xa0
> [ 47.165598] brcmu_pkt_buf_free_skb+0x44/0x68 [brcmutil]
> [ 47.171023] brcmf_txfinalize+0xec/0x190 [brcmfmac]
> [ 47.176016] brcmf_proto_bcdc_txcomplete+0x1c0/0x210 [brcmfmac]
> [ 47.182056] brcmf_sdio_sendfromq+0x8dc/0x1e80 [brcmfmac]
> [ 47.187568] brcmf_sdio_dpc+0xb48/0x2108 [brcmfmac]
> [ 47.192529] brcmf_sdio_dataworker+0xc8/0x238 [brcmfmac]
> [ 47.197859] process_one_work+0x7fc/0x1a80
> [ 47.201965] worker_thread+0x31c/0xc40
> [ 47.205726] kthread+0x2d8/0x370
> [ 47.208967] ret_from_fork+0x10/0x18
> [ 47.212546]
> [ 47.214051] The buggy address belongs to the object at ffffff803f588280
> [ 47.214051] which belongs to the cache skbuff_head_cache of size 208
> [ 47.227086] The buggy address is located 104 bytes inside of
> [ 47.227086] 208-byte region [ffffff803f588280, ffffff803f588350)
> [ 47.238814] The buggy address belongs to the page:
> [ 47.243618] page:ffffffff00dd6200 refcount:1 mapcount:0 mapping:ffffff804b6bf800 index:0xffffff803f589900 compound_mapcount: 0
> [ 47.255007] flags: 0x10200(slab|head)
> [ 47.258689] raw: 0000000000010200 ffffffff00dfa980 0000000200000002 ffffff804b6bf800
> [ 47.266439] raw: ffffff803f589900 0000000080190018 00000001ffffffff 0000000000000000
> [ 47.274180] page dumped because: kasan: bad access detected
> [ 47.279752]
> [ 47.281251] Memory state around the buggy address:
> [ 47.286051] ffffff803f588180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 47.293277] ffffff803f588200: fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> [ 47.300502] >ffffff803f588280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 47.307723] ^
> [ 47.314343] ffffff803f588300: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc
> [ 47.321569] ffffff803f588380: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
> [ 47.328789] ==================================================================
>
> Signed-off-by: Alexander Coffin <alex.coffin@xxxxxxxxxxxx>
> ---
> drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
> index 87aef211b35f..12ee8b7163fd 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
> @@ -296,6 +296,7 @@ static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff *skb,
> struct brcmf_pub *drvr = ifp->drvr;
> struct ethhdr *eh;
> int head_delta;
> + unsigned int tx_bytes = skb->len;
>
> brcmf_dbg(DATA, "Enter, bsscfgidx=%d\n", ifp->bsscfgidx);
>
> @@ -370,7 +371,7 @@ static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff *skb,
> ndev->stats.tx_dropped++;
> } else {
> ndev->stats.tx_packets++;
> - ndev->stats.tx_bytes += skb->len;
> + ndev->stats.tx_bytes += tx_bytes;
> }
>
> /* Return ok: we always eat the packet */
> --
> 2.30.2
>
