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net: stmmac: fix kernel panic due to NULL pointer dereference of plat->est

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In the case of taprio offload is not enabled, the error handling path
causes a kernel crash due to kernel NULL pointer deference.

Fix this by adding check for NULL before attempt to access 'plat->est'
on the mutex_lock() call.

The following kernel panic is observed without this patch:

RIP: 0010:mutex_lock+0x10/0x20
Call Trace:
tc_setup_taprio+0x482/0x560 [stmmac]
kmem_cache_alloc_trace+0x13f/0x490
taprio_disable_offload.isra.0+0x9d/0x180 [sch_taprio]
taprio_destroy+0x6c/0x100 [sch_taprio]
qdisc_create+0x2e5/0x4f0
tc_modify_qdisc+0x126/0x740
rtnetlink_rcv_msg+0x12b/0x380
_raw_spin_lock_irqsave+0x19/0x40
_raw_spin_unlock_irqrestore+0x18/0x30
create_object+0x212/0x340
rtnl_calcit.isra.0+0x110/0x110
netlink_rcv_skb+0x50/0x100
netlink_unicast+0x191/0x230
netlink_sendmsg+0x243/0x470
sock_sendmsg+0x5e/0x60
____sys_sendmsg+0x20b/0x280
copy_msghdr_from_user+0x5c/0x90
__mod_memcg_state+0x87/0xf0
 ___sys_sendmsg+0x7c/0xc0
lru_cache_add+0x7f/0xa0
_raw_spin_unlock+0x16/0x30
wp_page_copy+0x449/0x890
handle_mm_fault+0x921/0xfc0
__sys_sendmsg+0x59/0xa0
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
---[ end trace b1f19b24368a96aa ]---

Fixes: b60189e039 ("net: stmmac: Integrate EST with TAPRIO scheduler API")
Cc: <stable@vger.kernel.org> # 5.10.x
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Wong Vee Khee 2021-08-20 21:26:22 +08:00 committed by David S. Miller
parent 46002bf300
commit 82a44ae113
1 changed files with 7 additions and 5 deletions
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12
drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
View File

@ -884,11 +884,13 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
return 0;
disable:
mutex_lock(&priv->plat->est->lock);
priv->plat->est->enable = false;
stmmac_est_configure(priv, priv->ioaddr, priv->plat->est,
priv->plat->clk_ptp_rate);
mutex_unlock(&priv->plat->est->lock);
if (priv->plat->est) {
mutex_lock(&priv->plat->est->lock);
priv->plat->est->enable = false;
stmmac_est_configure(priv, priv->ioaddr, priv->plat->est,
priv->plat->clk_ptp_rate);
mutex_unlock(&priv->plat->est->lock);
}
priv->plat->fpe_cfg->enable = false;
stmmac_fpe_configure(priv, priv->ioaddr,