This patch fixes an exception that occurs during open()
when kdump is enabled. The sequence to reproduce the
exception is as follows:
a) enable kdump
b) trigger kdump via "echo c > /proc/sysrq-trigger"
c) kdump kernel executes
d) kdump kernel loads mlxbf_gige module
e) the mlxbf_gige module runs its open() as the
the "oob_net0" interface is brought up
f) mlxbf_gige module will experience an exception
during its open(), something like:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Mem abort info:
ESR = 0x0000000086000004
EC = 0x21: IABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
user pgtable: 4k pages, 48-bit VAs, pgdp=00000000e29a4000
[0000000000000000] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 0000000086000004 [#1] SMP
CPU: 0 PID: 812 Comm: NetworkManager Tainted: G OE 5.15.0-1035-bluefield #37-Ubuntu
Hardware name: https://www.mellanox.com BlueField-3 SmartNIC Main Card/BlueField-3 SmartNIC Main Card, BIOS 4.6.0.13024 Jan 19 2024
pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : 0x0
lr : __napi_poll+0x40/0x230
sp : ffff800008003e00
x29: ffff800008003e00 x28: 0000000000000000 x27: 00000000ffffffff
x26: ffff000066027238 x25: ffff00007cedec00 x24: ffff800008003ec8
x23: 000000000000012c x22: ffff800008003eb7 x21: 0000000000000000
x20: 0000000000000001 x19: ffff000066027238 x18: 0000000000000000
x17: ffff578fcb450000 x16: ffffa870b083c7c0 x15: 0000aaab010441d0
x14: 0000000000000001 x13: 00726f7272655f65 x12: 6769675f6662786c
x11: 0000000000000000 x10: 0000000000000000 x9 : ffffa870b0842398
x8 : 0000000000000004 x7 : fe5a48b9069706ea x6 : 17fdb11fc84ae0d2
x5 : d94a82549d594f35 x4 : 0000000000000000 x3 : 0000000000400100
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000066027238
Call trace:
0x0
net_rx_action+0x178/0x360
__do_softirq+0x15c/0x428
__irq_exit_rcu+0xac/0xec
irq_exit+0x18/0x2c
handle_domain_irq+0x6c/0xa0
gic_handle_irq+0xec/0x1b0
call_on_irq_stack+0x20/0x2c
do_interrupt_handler+0x5c/0x70
el1_interrupt+0x30/0x50
el1h_64_irq_handler+0x18/0x2c
el1h_64_irq+0x7c/0x80
__setup_irq+0x4c0/0x950
request_threaded_irq+0xf4/0x1bc
mlxbf_gige_request_irqs+0x68/0x110 [mlxbf_gige]
mlxbf_gige_open+0x5c/0x170 [mlxbf_gige]
__dev_open+0x100/0x220
__dev_change_flags+0x16c/0x1f0
dev_change_flags+0x2c/0x70
do_setlink+0x220/0xa40
__rtnl_newlink+0x56c/0x8a0
rtnl_newlink+0x58/0x84
rtnetlink_rcv_msg+0x138/0x3c4
netlink_rcv_skb+0x64/0x130
rtnetlink_rcv+0x20/0x30
netlink_unicast+0x2ec/0x360
netlink_sendmsg+0x278/0x490
__sock_sendmsg+0x5c/0x6c
____sys_sendmsg+0x290/0x2d4
___sys_sendmsg+0x84/0xd0
__sys_sendmsg+0x70/0xd0
__arm64_sys_sendmsg+0x2c/0x40
invoke_syscall+0x78/0x100
el0_svc_common.constprop.0+0x54/0x184
do_el0_svc+0x30/0xac
el0_svc+0x48/0x160
el0t_64_sync_handler+0xa4/0x12c
el0t_64_sync+0x1a4/0x1a8
Code: bad PC value
---[ end trace 7d1c3f3bf9d81885 ]---
Kernel panic - not syncing: Oops: Fatal exception in interrupt
Kernel Offset: 0x2870a7a00000 from 0xffff800008000000
PHYS_OFFSET: 0x80000000
CPU features: 0x0,000005c1,a3332a5a
Memory Limit: none
---[ end Kernel panic - not syncing: Oops: Fatal exception in interrupt ]---
The exception happens because there is a pending RX interrupt before the
call to request_irq(RX IRQ) executes. Then, the RX IRQ handler fires
immediately after this request_irq() completes. The RX IRQ handler runs
"napi_schedule()" before NAPI is fully initialized via "netif_napi_add()"
and "napi_enable()", both which happen later in the open() logic.
This patch fixes the issue by re-ordering the logic in mlxbf_gige open()
so that the request_irq() calls execute after NAPI is fully initialized.
Fixes: f92e1869d74e ("Add Mellanox BlueField Gigabit Ethernet driver")
Signed-off-by: David Thompson <[email protected]>
Reviewed-by: Asmaa Mnebhi <[email protected]>
---
.../mellanox/mlxbf_gige/mlxbf_gige_main.c | 21 ++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_main.c b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_main.c
index 3d09fa54598f..77134ca92938 100644
--- a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_main.c
+++ b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_main.c
@@ -139,13 +139,10 @@ static int mlxbf_gige_open(struct net_device *netdev)
control |= MLXBF_GIGE_CONTROL_PORT_EN;
writeq(control, priv->base + MLXBF_GIGE_CONTROL);
- err = mlxbf_gige_request_irqs(priv);
- if (err)
- return err;
mlxbf_gige_cache_stats(priv);
err = mlxbf_gige_clean_port(priv);
if (err)
- goto free_irqs;
+ return err;
/* Clear driver's valid_polarity to match hardware,
* since the above call to clean_port() resets the
@@ -157,7 +154,7 @@ static int mlxbf_gige_open(struct net_device *netdev)
err = mlxbf_gige_tx_init(priv);
if (err)
- goto free_irqs;
+ goto phy_deinit;
err = mlxbf_gige_rx_init(priv);
if (err)
goto tx_deinit;
@@ -166,6 +163,10 @@ static int mlxbf_gige_open(struct net_device *netdev)
napi_enable(&priv->napi);
netif_start_queue(netdev);
+ err = mlxbf_gige_request_irqs(priv);
+ if (err)
+ goto napi_deinit;
+
/* Set bits in INT_EN that we care about */
int_en = MLXBF_GIGE_INT_EN_HW_ACCESS_ERROR |
MLXBF_GIGE_INT_EN_TX_CHECKSUM_INPUTS |
@@ -182,11 +183,17 @@ static int mlxbf_gige_open(struct net_device *netdev)
return 0;
+napi_deinit:
+ netif_stop_queue(netdev);
+ napi_disable(&priv->napi);
+ netif_napi_del(&priv->napi);
+ mlxbf_gige_rx_deinit(priv);
+
tx_deinit:
mlxbf_gige_tx_deinit(priv);
-free_irqs:
- mlxbf_gige_free_irqs(priv);
+phy_deinit:
+ phy_stop(phydev);
return err;
}
--
2.30.1
Fri, Mar 15, 2024 at 03:56:09PM CET, [email protected] wrote:
>This patch fixes an exception that occurs during open()
Don't talk about "this patch" in the patch description. Be imperative to
the codebase, tell it what to do. In both patch description and subject.
Much easier to follow then.
>when kdump is enabled. The sequence to reproduce the
>exception is as follows:
>a) enable kdump
>b) trigger kdump via "echo c > /proc/sysrq-trigger"
>c) kdump kernel executes
>d) kdump kernel loads mlxbf_gige module
>e) the mlxbf_gige module runs its open() as the
> the "oob_net0" interface is brought up
>f) mlxbf_gige module will experience an exception
> during its open(), something like:
>
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
> Mem abort info:
> ESR = 0x0000000086000004
> EC = 0x21: IABT (current EL), IL = 32 bits
> SET = 0, FnV = 0
> EA = 0, S1PTW = 0
> FSC = 0x04: level 0 translation fault
> user pgtable: 4k pages, 48-bit VAs, pgdp=00000000e29a4000
> [0000000000000000] pgd=0000000000000000, p4d=0000000000000000
> Internal error: Oops: 0000000086000004 [#1] SMP
> CPU: 0 PID: 812 Comm: NetworkManager Tainted: G OE 5.15.0-1035-bluefield #37-Ubuntu
> Hardware name: https://www.mellanox.com BlueField-3 SmartNIC Main Card/BlueField-3 SmartNIC Main Card, BIOS 4.6.0.13024 Jan 19 2024
> pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : 0x0
> lr : __napi_poll+0x40/0x230
> sp : ffff800008003e00
> x29: ffff800008003e00 x28: 0000000000000000 x27: 00000000ffffffff
> x26: ffff000066027238 x25: ffff00007cedec00 x24: ffff800008003ec8
> x23: 000000000000012c x22: ffff800008003eb7 x21: 0000000000000000
> x20: 0000000000000001 x19: ffff000066027238 x18: 0000000000000000
> x17: ffff578fcb450000 x16: ffffa870b083c7c0 x15: 0000aaab010441d0
> x14: 0000000000000001 x13: 00726f7272655f65 x12: 6769675f6662786c
> x11: 0000000000000000 x10: 0000000000000000 x9 : ffffa870b0842398
> x8 : 0000000000000004 x7 : fe5a48b9069706ea x6 : 17fdb11fc84ae0d2
> x5 : d94a82549d594f35 x4 : 0000000000000000 x3 : 0000000000400100
> x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000066027238
> Call trace:
> 0x0
> net_rx_action+0x178/0x360
> __do_softirq+0x15c/0x428
> __irq_exit_rcu+0xac/0xec
> irq_exit+0x18/0x2c
> handle_domain_irq+0x6c/0xa0
> gic_handle_irq+0xec/0x1b0
> call_on_irq_stack+0x20/0x2c
> do_interrupt_handler+0x5c/0x70
> el1_interrupt+0x30/0x50
> el1h_64_irq_handler+0x18/0x2c
> el1h_64_irq+0x7c/0x80
> __setup_irq+0x4c0/0x950
> request_threaded_irq+0xf4/0x1bc
> mlxbf_gige_request_irqs+0x68/0x110 [mlxbf_gige]
> mlxbf_gige_open+0x5c/0x170 [mlxbf_gige]
> __dev_open+0x100/0x220
> __dev_change_flags+0x16c/0x1f0
> dev_change_flags+0x2c/0x70
> do_setlink+0x220/0xa40
> __rtnl_newlink+0x56c/0x8a0
> rtnl_newlink+0x58/0x84
> rtnetlink_rcv_msg+0x138/0x3c4
> netlink_rcv_skb+0x64/0x130
> rtnetlink_rcv+0x20/0x30
> netlink_unicast+0x2ec/0x360
> netlink_sendmsg+0x278/0x490
> __sock_sendmsg+0x5c/0x6c
> ____sys_sendmsg+0x290/0x2d4
> ___sys_sendmsg+0x84/0xd0
> __sys_sendmsg+0x70/0xd0
> __arm64_sys_sendmsg+0x2c/0x40
> invoke_syscall+0x78/0x100
> el0_svc_common.constprop.0+0x54/0x184
> do_el0_svc+0x30/0xac
> el0_svc+0x48/0x160
> el0t_64_sync_handler+0xa4/0x12c
> el0t_64_sync+0x1a4/0x1a8
> Code: bad PC value
> ---[ end trace 7d1c3f3bf9d81885 ]---
> Kernel panic - not syncing: Oops: Fatal exception in interrupt
> Kernel Offset: 0x2870a7a00000 from 0xffff800008000000
> PHYS_OFFSET: 0x80000000
> CPU features: 0x0,000005c1,a3332a5a
> Memory Limit: none
> ---[ end Kernel panic - not syncing: Oops: Fatal exception in interrupt ]---
>
>The exception happens because there is a pending RX interrupt before the
>call to request_irq(RX IRQ) executes. Then, the RX IRQ handler fires
>immediately after this request_irq() completes. The RX IRQ handler runs
>"napi_schedule()" before NAPI is fully initialized via "netif_napi_add()"
>and "napi_enable()", both which happen later in the open() logic.
>
>This patch fixes the issue by re-ordering the logic in mlxbf_gige open()
>so that the request_irq() calls execute after NAPI is fully initialized.
Same here.
>
>Fixes: f92e1869d74e ("Add Mellanox BlueField Gigabit Ethernet driver")
>Signed-off-by: David Thompson <[email protected]>
>Reviewed-by: Asmaa Mnebhi <[email protected]>
The patch itself looks okay.
pw-bot: cr
>---
> .../mellanox/mlxbf_gige/mlxbf_gige_main.c | 21 ++++++++++++-------
> 1 file changed, 14 insertions(+), 7 deletions(-)
>
>diff --git a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_main.c b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_main.c
>index 3d09fa54598f..77134ca92938 100644
>--- a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_main.c
>+++ b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_main.c
>@@ -139,13 +139,10 @@ static int mlxbf_gige_open(struct net_device *netdev)
> control |= MLXBF_GIGE_CONTROL_PORT_EN;
> writeq(control, priv->base + MLXBF_GIGE_CONTROL);
>
>- err = mlxbf_gige_request_irqs(priv);
>- if (err)
>- return err;
> mlxbf_gige_cache_stats(priv);
> err = mlxbf_gige_clean_port(priv);
> if (err)
>- goto free_irqs;
>+ return err;
>
> /* Clear driver's valid_polarity to match hardware,
> * since the above call to clean_port() resets the
>@@ -157,7 +154,7 @@ static int mlxbf_gige_open(struct net_device *netdev)
>
> err = mlxbf_gige_tx_init(priv);
> if (err)
>- goto free_irqs;
>+ goto phy_deinit;
> err = mlxbf_gige_rx_init(priv);
> if (err)
> goto tx_deinit;
>@@ -166,6 +163,10 @@ static int mlxbf_gige_open(struct net_device *netdev)
> napi_enable(&priv->napi);
> netif_start_queue(netdev);
>
>+ err = mlxbf_gige_request_irqs(priv);
>+ if (err)
>+ goto napi_deinit;
>+
> /* Set bits in INT_EN that we care about */
> int_en = MLXBF_GIGE_INT_EN_HW_ACCESS_ERROR |
> MLXBF_GIGE_INT_EN_TX_CHECKSUM_INPUTS |
>@@ -182,11 +183,17 @@ static int mlxbf_gige_open(struct net_device *netdev)
>
> return 0;
>
>+napi_deinit:
>+ netif_stop_queue(netdev);
>+ napi_disable(&priv->napi);
>+ netif_napi_del(&priv->napi);
>+ mlxbf_gige_rx_deinit(priv);
>+
> tx_deinit:
> mlxbf_gige_tx_deinit(priv);
>
>-free_irqs:
>- mlxbf_gige_free_irqs(priv);
>+phy_deinit:
>+ phy_stop(phydev);
> return err;
> }
>
>--
>2.30.1
>
>
On Fri, 2024-03-15 at 10:56 -0400, David Thompson wrote:
> This patch fixes an exception that occurs during open()
> when kdump is enabled. The sequence to reproduce the
> exception is as follows:
> a) enable kdump
> b) trigger kdump via "echo c > /proc/sysrq-trigger"
> c) kdump kernel executes
> d) kdump kernel loads mlxbf_gige module
> e) the mlxbf_gige module runs its open() as the
> the "oob_net0" interface is brought up
> f) mlxbf_gige module will experience an exception
> during its open(), something like:
>
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
> Mem abort info:
> ESR = 0x0000000086000004
> EC = 0x21: IABT (current EL), IL = 32 bits
> SET = 0, FnV = 0
> EA = 0, S1PTW = 0
> FSC = 0x04: level 0 translation fault
> user pgtable: 4k pages, 48-bit VAs, pgdp=00000000e29a4000
> [0000000000000000] pgd=0000000000000000, p4d=0000000000000000
> Internal error: Oops: 0000000086000004 [#1] SMP
> CPU: 0 PID: 812 Comm: NetworkManager Tainted: G OE 5.15.0-1035-bluefield #37-Ubuntu
> Hardware name: https://www.mellanox.com BlueField-3 SmartNIC Main Card/BlueField-3 SmartNIC Main Card, BIOS 4.6.0.13024 Jan 19 2024
> pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : 0x0
> lr : __napi_poll+0x40/0x230
> sp : ffff800008003e00
> x29: ffff800008003e00 x28: 0000000000000000 x27: 00000000ffffffff
> x26: ffff000066027238 x25: ffff00007cedec00 x24: ffff800008003ec8
> x23: 000000000000012c x22: ffff800008003eb7 x21: 0000000000000000
> x20: 0000000000000001 x19: ffff000066027238 x18: 0000000000000000
> x17: ffff578fcb450000 x16: ffffa870b083c7c0 x15: 0000aaab010441d0
> x14: 0000000000000001 x13: 00726f7272655f65 x12: 6769675f6662786c
> x11: 0000000000000000 x10: 0000000000000000 x9 : ffffa870b0842398
> x8 : 0000000000000004 x7 : fe5a48b9069706ea x6 : 17fdb11fc84ae0d2
> x5 : d94a82549d594f35 x4 : 0000000000000000 x3 : 0000000000400100
> x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000066027238
> Call trace:
> 0x0
> net_rx_action+0x178/0x360
> __do_softirq+0x15c/0x428
> __irq_exit_rcu+0xac/0xec
> irq_exit+0x18/0x2c
> handle_domain_irq+0x6c/0xa0
> gic_handle_irq+0xec/0x1b0
> call_on_irq_stack+0x20/0x2c
> do_interrupt_handler+0x5c/0x70
> el1_interrupt+0x30/0x50
> el1h_64_irq_handler+0x18/0x2c
> el1h_64_irq+0x7c/0x80
> __setup_irq+0x4c0/0x950
> request_threaded_irq+0xf4/0x1bc
> mlxbf_gige_request_irqs+0x68/0x110 [mlxbf_gige]
> mlxbf_gige_open+0x5c/0x170 [mlxbf_gige]
> __dev_open+0x100/0x220
> __dev_change_flags+0x16c/0x1f0
> dev_change_flags+0x2c/0x70
> do_setlink+0x220/0xa40
> __rtnl_newlink+0x56c/0x8a0
> rtnl_newlink+0x58/0x84
> rtnetlink_rcv_msg+0x138/0x3c4
> netlink_rcv_skb+0x64/0x130
> rtnetlink_rcv+0x20/0x30
> netlink_unicast+0x2ec/0x360
> netlink_sendmsg+0x278/0x490
> __sock_sendmsg+0x5c/0x6c
> ____sys_sendmsg+0x290/0x2d4
> ___sys_sendmsg+0x84/0xd0
> __sys_sendmsg+0x70/0xd0
> __arm64_sys_sendmsg+0x2c/0x40
> invoke_syscall+0x78/0x100
> el0_svc_common.constprop.0+0x54/0x184
> do_el0_svc+0x30/0xac
> el0_svc+0x48/0x160
> el0t_64_sync_handler+0xa4/0x12c
> el0t_64_sync+0x1a4/0x1a8
> Code: bad PC value
> ---[ end trace 7d1c3f3bf9d81885 ]---
> Kernel panic - not syncing: Oops: Fatal exception in interrupt
> Kernel Offset: 0x2870a7a00000 from 0xffff800008000000
> PHYS_OFFSET: 0x80000000
> CPU features: 0x0,000005c1,a3332a5a
> Memory Limit: none
> ---[ end Kernel panic - not syncing: Oops: Fatal exception in interrupt ]---
>
> The exception happens because there is a pending RX interrupt before the
> call to request_irq(RX IRQ) executes. Then, the RX IRQ handler fires
> immediately after this request_irq() completes. The RX IRQ handler runs
> "napi_schedule()" before NAPI is fully initialized via "netif_napi_add()"
> and "napi_enable()", both which happen later in the open() logic.
>
> This patch fixes the issue by re-ordering the logic in mlxbf_gige open()
> so that the request_irq() calls execute after NAPI is fully initialized.
It also adds a missing phy_stop(phydev) in the error path. It's worth
mentioning in the changelog or possibly place into a separate patch.
Cheers,
Paolo