4.17-stable review patch. If anyone has any objections, please let me know.
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From: Haiyue Wang haiyue.wang@linux.intel.com
[ Upstream commit dc0f0a026d33819bb82d5c26ab2fca838e2004be ]
When kcs_bmc_handle_event calls kcs_force_abort function to handle the not open (no user running) KCS channel transaction, the returned status value -ENODEV causes the low level IRQ handler indicating that the irq was not for him by returning IRQ_NONE. After some time, this IRQ will be treated to be spurious one, and the exception dump happens.
irq 30: nobody cared (try booting with the "irqpoll" option) CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.10.15-npcm750 #1 Hardware name: NPCMX50 Chip family [<c010b264>] (unwind_backtrace) from [<c0106930>] (show_stack+0x20/0x24) [<c0106930>] (show_stack) from [<c03dad38>] (dump_stack+0x8c/0xa0) [<c03dad38>] (dump_stack) from [<c0168810>] (__report_bad_irq+0x3c/0xdc) [<c0168810>] (__report_bad_irq) from [<c0168c34>] (note_interrupt+0x29c/0x2ec) [<c0168c34>] (note_interrupt) from [<c0165c80>] (handle_irq_event_percpu+0x5c/0x68) [<c0165c80>] (handle_irq_event_percpu) from [<c0165cd4>] (handle_irq_event+0x48/0x6c) [<c0165cd4>] (handle_irq_event) from [<c0169664>] (handle_fasteoi_irq+0xc8/0x198) [<c0169664>] (handle_fasteoi_irq) from [<c016529c>] (__handle_domain_irq+0x90/0xe8) [<c016529c>] (__handle_domain_irq) from [<c01014bc>] (gic_handle_irq+0x58/0x9c) [<c01014bc>] (gic_handle_irq) from [<c010752c>] (__irq_svc+0x6c/0x90) Exception stack(0xc0a01de8 to 0xc0a01e30) 1de0: 00002080 c0a6fbc0 00000000 00000000 00000000 c096d294 1e00: 00000000 00000001 dc406400 f03ff100 00000082 c0a01e94 c0a6fbc0 c0a01e38 1e20: 00200102 c01015bc 60000113 ffffffff [<c010752c>] (__irq_svc) from [<c01015bc>] (__do_softirq+0xbc/0x358) [<c01015bc>] (__do_softirq) from [<c011c798>] (irq_exit+0xb8/0xec) [<c011c798>] (irq_exit) from [<c01652a0>] (__handle_domain_irq+0x94/0xe8) [<c01652a0>] (__handle_domain_irq) from [<c01014bc>] (gic_handle_irq+0x58/0x9c) [<c01014bc>] (gic_handle_irq) from [<c010752c>] (__irq_svc+0x6c/0x90) Exception stack(0xc0a01ef8 to 0xc0a01f40) 1ee0: 00000000 000003ae 1f00: dcc0f338 c0111060 c0a00000 c0a0cc44 c0a0cbe4 c0a1c22b c07bc218 00000001 1f20: dcffca40 c0a01f54 c0a01f58 c0a01f48 c0103524 c0103528 60000013 ffffffff [<c010752c>] (__irq_svc) from [<c0103528>] (arch_cpu_idle+0x48/0x4c) [<c0103528>] (arch_cpu_idle) from [<c0681390>] (default_idle_call+0x30/0x3c) [<c0681390>] (default_idle_call) from [<c0156f24>] (do_idle+0xc8/0x134) [<c0156f24>] (do_idle) from [<c015722c>] (cpu_startup_entry+0x28/0x2c) [<c015722c>] (cpu_startup_entry) from [<c067ad74>] (rest_init+0x84/0x88) [<c067ad74>] (rest_init) from [<c0900d44>] (start_kernel+0x388/0x394) [<c0900d44>] (start_kernel) from [<0000807c>] (0x807c) handlers: [<c041c5dc>] npcm7xx_kcs_irq Disabling IRQ #30
It needs to change the returned status from -ENODEV to 0. The -ENODEV was originally used to tell the low level IRQ handler that no user was running, but not consider the IRQ handling desgin.
And multiple KCS channels share one IRQ handler, it needs to check the IBF flag before doing force abort. If the IBF is set, after handling, return 0 to low level IRQ handler to indicate that the IRQ is handled.
Signed-off-by: Haiyue Wang haiyue.wang@linux.intel.com Signed-off-by: Corey Minyard cminyard@mvista.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/ipmi/kcs_bmc.c | 31 ++++++++++--------------------- 1 file changed, 10 insertions(+), 21 deletions(-)
--- a/drivers/char/ipmi/kcs_bmc.c +++ b/drivers/char/ipmi/kcs_bmc.c @@ -210,34 +210,23 @@ static void kcs_bmc_handle_cmd(struct kc int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc) { unsigned long flags; - int ret = 0; + int ret = -ENODATA; u8 status;
spin_lock_irqsave(&kcs_bmc->lock, flags);
- if (!kcs_bmc->running) { - kcs_force_abort(kcs_bmc); - ret = -ENODEV; - goto out_unlock; - } - - status = read_status(kcs_bmc) & (KCS_STATUS_IBF | KCS_STATUS_CMD_DAT); - - switch (status) { - case KCS_STATUS_IBF | KCS_STATUS_CMD_DAT: - kcs_bmc_handle_cmd(kcs_bmc); - break; - - case KCS_STATUS_IBF: - kcs_bmc_handle_data(kcs_bmc); - break; + status = read_status(kcs_bmc); + if (status & KCS_STATUS_IBF) { + if (!kcs_bmc->running) + kcs_force_abort(kcs_bmc); + else if (status & KCS_STATUS_CMD_DAT) + kcs_bmc_handle_cmd(kcs_bmc); + else + kcs_bmc_handle_data(kcs_bmc);
- default: - ret = -ENODATA; - break; + ret = 0; }
-out_unlock: spin_unlock_irqrestore(&kcs_bmc->lock, flags);
return ret;