| Message ID | de4c64ccac9084952c56a06a8171d738604c4770.1670678513.git.piergiorgio.beruto@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | ede5a389852d3640a28e7187fb32b7f204380901 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v2,net,1/1] stmmac: fix potential division by 0 | expand |
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
Hello: This patch was applied to netdev/net.git (master) by Jakub Kicinski <kuba@kernel.org>: On Sat, 10 Dec 2022 23:37:22 +0100 you 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. > > [...] Here is the summary with links: - [v2,net,1/1] stmmac: fix potential division by 0 https://git.kernel.org/netdev/net/c/ede5a389852d You are awesome, thank you!
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c index 764832f4dae1..8b50f03056b7 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c @@ -47,7 +47,8 @@ static void config_sub_second_increment(void __iomem *ioaddr, if (!(value & PTP_TCR_TSCTRLSSR)) data = (data * 1000) / 465; - data &= PTP_SSIR_SSINC_MASK; + if (data > PTP_SSIR_SSINC_MAX) + data = PTP_SSIR_SSINC_MAX; reg_value = data; if (gmac4) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h index 53172a439810..bf619295d079 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h @@ -64,7 +64,7 @@ #define PTP_TCR_TSENMACADDR BIT(18) /* SSIR defines */ -#define PTP_SSIR_SSINC_MASK 0xff +#define PTP_SSIR_SSINC_MAX 0xff #define GMAC4_PTP_SSIR_SSINC_SHIFT 16 /* Auxiliary Control defines */
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") --- drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c | 3 ++- drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-)