From: Andrew Lunn <andrew@lunn.ch>
To: Piergiorgio Beruto <piergiorgio.beruto@gmail.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>,
Alexandre Torgue <alexandre.torgue@foss.st.com>,
Jose Abreu <joabreu@synopsys.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Richard Cochran <richardcochran@gmail.com>,
Julien Beraud <julien.beraud@orolia.com>,
netdev@vger.kernel.org
Subject: Re: [PATCH v2 net 1/1] stmmac: fix potential division by 0
Date: Sun, 11 Dec 2022 12:18:49 +0100 [thread overview]
Message-ID: <Y5W8mbkdi1E1MFzh@lunn.ch> (raw)
In-Reply-To: <de4c64ccac9084952c56a06a8171d738604c4770.1670678513.git.piergiorgio.beruto@gmail.com>
On Sat, Dec 10, 2022 at 11:37:22PM +0100, Piergiorgio Beruto wrote:
> When the MAC is connected to a 10 Mb/s PHY and the PTP clock is derived
> from the MAC reference clock (default), the clk_ptp_rate becomes too
> small and the calculated sub second increment becomes 0 when computed by
> the stmmac_config_sub_second_increment() function within
> stmmac_init_tstamp_counter().
>
> Therefore, the subsequent div_u64 in stmmac_init_tstamp_counter()
> operation triggers a divide by 0 exception as shown below.
>
> [ 95.062067] socfpga-dwmac ff700000.ethernet eth0: Register MEM_TYPE_PAGE_POOL RxQ-0
> [ 95.076440] socfpga-dwmac ff700000.ethernet eth0: PHY [stmmac-0:08] driver [NCN26000] (irq=49)
> [ 95.095964] dwmac1000: Master AXI performs any burst length
> [ 95.101588] socfpga-dwmac ff700000.ethernet eth0: No Safety Features support found
> [ 95.109428] Division by zero in kernel.
> [ 95.113447] CPU: 0 PID: 239 Comm: ifconfig Not tainted 6.1.0-rc7-centurion3-1.0.3.0-01574-gb624218205b7-dirty #77
> [ 95.123686] Hardware name: Altera SOCFPGA
> [ 95.127695] unwind_backtrace from show_stack+0x10/0x14
> [ 95.132938] show_stack from dump_stack_lvl+0x40/0x4c
> [ 95.137992] dump_stack_lvl from Ldiv0+0x8/0x10
> [ 95.142527] Ldiv0 from __aeabi_uidivmod+0x8/0x18
> [ 95.147232] __aeabi_uidivmod from div_u64_rem+0x1c/0x40
> [ 95.152552] div_u64_rem from stmmac_init_tstamp_counter+0xd0/0x164
> [ 95.158826] stmmac_init_tstamp_counter from stmmac_hw_setup+0x430/0xf00
> [ 95.165533] stmmac_hw_setup from __stmmac_open+0x214/0x2d4
> [ 95.171117] __stmmac_open from stmmac_open+0x30/0x44
> [ 95.176182] stmmac_open from __dev_open+0x11c/0x134
> [ 95.181172] __dev_open from __dev_change_flags+0x168/0x17c
> [ 95.186750] __dev_change_flags from dev_change_flags+0x14/0x50
> [ 95.192662] dev_change_flags from devinet_ioctl+0x2b4/0x604
> [ 95.198321] devinet_ioctl from inet_ioctl+0x1ec/0x214
> [ 95.203462] inet_ioctl from sock_ioctl+0x14c/0x3c4
> [ 95.208354] sock_ioctl from vfs_ioctl+0x20/0x38
> [ 95.212984] vfs_ioctl from sys_ioctl+0x250/0x844
> [ 95.217691] sys_ioctl from ret_fast_syscall+0x0/0x4c
> [ 95.222743] Exception stack(0xd0ee1fa8 to 0xd0ee1ff0)
> [ 95.227790] 1fa0: 00574c4f be9aeca4 00000003 00008914 be9aeca4 be9aec50
> [ 95.235945] 1fc0: 00574c4f be9aeca4 0059f078 00000036 be9aee8c be9aef7a 00000015 00000000
> [ 95.244096] 1fe0: 005a01f0 be9aec38 004d7484 b6e67d74
>
> Signed-off-by: Piergiorgio Beruto <piergiorgio.beruto@gmail.com>
> Fixes: 91a2559c1dc5 ("net: stmmac: Fix sub-second increment")
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Andrew
next prev parent reply other threads:[~2022-12-11 11:19 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-10 22:37 [PATCH v2 net 1/1] stmmac: fix potential division by 0 Piergiorgio Beruto
2022-12-11 11:18 ` Andrew Lunn [this message]
2022-12-12 23:20 ` patchwork-bot+netdevbpf
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