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07d9958739
The .get_stats64 callback runs in atomic context, but on
MDIO-connected switches every register read acquires the MDIO bus
mutex, which can sleep:
[ 12.645973] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:609
[ 12.654442] in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 759, name: grep
[ 12.663377] preempt_count: 0, expected: 0
[ 12.667410] RCU nest depth: 1, expected: 0
[ 12.671511] INFO: lockdep is turned off.
[ 12.675441] CPU: 0 UID: 0 PID: 759 Comm: grep Tainted: G S W 7.0.0+ #0 PREEMPT
[ 12.675453] Tainted: [S]=CPU_OUT_OF_SPEC, [W]=WARN
[ 12.675456] Hardware name: Bananapi BPI-R64 (DT)
[ 12.675459] Call trace:
[ 12.675462] show_stack+0x14/0x1c (C)
[ 12.675477] dump_stack_lvl+0x68/0x8c
[ 12.675487] dump_stack+0x14/0x1c
[ 12.675495] __might_resched+0x14c/0x220
[ 12.675504] __might_sleep+0x44/0x80
[ 12.675511] __mutex_lock+0x50/0xb10
[ 12.675523] mutex_lock_nested+0x20/0x30
[ 12.675532] mt7530_get_stats64+0x40/0x2ac
[ 12.675542] dsa_user_get_stats64+0x2c/0x40
[ 12.675553] dev_get_stats+0x44/0x1e0
[ 12.675564] dev_seq_printf_stats+0x24/0xe0
[ 12.675575] dev_seq_show+0x14/0x3c
[ 12.675583] seq_read_iter+0x37c/0x480
[ 12.675595] seq_read+0xd0/0xec
[ 12.675605] proc_reg_read+0x94/0xe4
[ 12.675615] vfs_read+0x98/0x29c
[ 12.675625] ksys_read+0x54/0xdc
[ 12.675633] __arm64_sys_read+0x18/0x20
[ 12.675642] invoke_syscall.constprop.0+0x54/0xec
[ 12.675653] do_el0_svc+0x3c/0xb4
[ 12.675662] el0_svc+0x38/0x200
[ 12.675670] el0t_64_sync_handler+0x98/0xdc
[ 12.675679] el0t_64_sync+0x158/0x15c
For MDIO-connected switches, poll MIB counters asynchronously using a
delayed workqueue every second and let .get_stats64 return the cached
values under a spinlock. A mod_delayed_work() call on each read
triggers an immediate refresh so counters stay responsive when queried
more frequently.
MMIO-connected switches (MT7988, EN7581, AN7583) are not affected
because their regmap does not sleep, so they continue to read MIB
counters directly in .get_stats64.
Fixes:
|
||
|---|---|---|
| .. | ||
| b53 | ||
| hirschmann | ||
| lantiq | ||
| microchip | ||
| mv88e6xxx | ||
| mxl862xx | ||
| ocelot | ||
| qca | ||
| realtek | ||
| sja1105 | ||
| xrs700x | ||
| bcm_sf2_cfp.c | ||
| bcm_sf2_regs.h | ||
| bcm_sf2.c | ||
| bcm_sf2.h | ||
| dsa_loop.c | ||
| Kconfig | ||
| ks8995.c | ||
| lan9303_i2c.c | ||
| lan9303_mdio.c | ||
| lan9303-core.c | ||
| lan9303.h | ||
| Makefile | ||
| mt7530-mdio.c | ||
| mt7530-mmio.c | ||
| mt7530.c | ||
| mt7530.h | ||
| mv88e6060.c | ||
| mv88e6060.h | ||
| rzn1_a5psw.c | ||
| rzn1_a5psw.h | ||
| vitesse-vsc73xx-core.c | ||
| vitesse-vsc73xx-platform.c | ||
| vitesse-vsc73xx-spi.c | ||
| vitesse-vsc73xx.h | ||
| yt921x.c | ||
| yt921x.h | ||