[RFC PATCH V2] ipmi: ssif: Fix out of bounds in write_next_byte()

From: Wu Bo
Date: Mon Sep 21 2020 - 09:50:16 EST

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In my virtual machine (have 4 cpus), Use mce_inject to inject errors
into the system. After mce-inject injects an uncorrectable error,
there is a probability that the virtual machine is not reset immediately,
but hangs for more than 3000 seconds, and appeared unable to
handle kernel paging request.

The analysis reasons are as follows:
1) MCE appears on all CPUs, Currently all CPUs are in the NMI interrupt
context. cpu0 is the first to seize the opportunity to run panic
routines, and panic event should stop the other processors before
do ipmi flush_messages(). but cpu1, cpu2 and cpu3 has already
in NMI interrupt context, So the Second NMI interrupt(IPI)
will not be processed again by cpu1, cpu2 and cpu3.
At this time, cpu1,cpu2 and cpu3 did not stopped.

2) cpu1, cpu2 and cpu3 are waitting for cpu0 to finish the panic process.
if a timeout waiting for other CPUs happened, do wait_for_panic(),
the irq is enabled in the wait_for_panic() function.

3) ipmi IRQ occurs on the cpu3, and the cpu0 is doing the panic,
they have the opportunity to call the smi_event_handler()
function concurrently. the ipmi IRQ affects the panic process of cpu0.

CPU0 CPU3

|-nmi_handle do mce_panic |-nmi_handle do_machine_check
| |
|-panic() |-wait_for_panic()
| |
|-stop other cpus ---- NMI ------> (Ignore, already in nmi interrupt)
| |
|-notifier call(ipmi panic_event) |<-ipmi IRQ occurs
| |
\|/ \|/
do smi_event_handler() do smi_event_handler()

The current scene encountered is a simulation injection error of the mce software,
and it is not confirmed whether there are other similar scenes.

so add the try spinlocks in the IPMI panic handler to solve the concurrency problem of
panic process and IRQ process, and also to prevent the panic process from deadlock.

Steps to reproduce (Have a certain probability):
1. # vim /tmp/uncorrected
CPU 1 BANK 4
STATUS uncorrected 0xc0
MCGSTATUS EIPV MCIP
ADDR 0x1234
RIP 0xdeadbabe
RAISINGCPU 0
MCGCAP SER CMCI TES 0x6

2. # modprobe mce_inject
3. # cd /tmp
4. # mce-inject uncorrected

The logs:
[ 55.086670] core: [Hardware Error]: RIP 00:<00000000deadbabe>
[ 55.086671] core: [Hardware Error]: TSC 2e11aff65eea ADDR 1234
[ 55.086673] core: [Hardware Error]: PROCESSOR 0:50654 TIME 1598967234 SOCKET 0 APIC 1 microcode 1
[ 55.086674] core: [Hardware Error]: Run the above through 'mcelog --ascii'
[ 55.086675] core: [Hardware Error]: Machine check: In kernel and no restart IP
[ 55.086676] Kernel panic - not syncing: Fatal machine check
[ 55.086677] kernel fault(0x5) notification starting on CPU 0
[ 55.086682] kernel fault(0x5) notification finished on CPU 0
[ 4767.947960] BUG: unable to handle kernel paging request at ffff893e40000000
[ 4767.947962] PGD 13c001067 P4D 13c001067 PUD 0
[ 4767.947965] Oops: 0000 [#1] SMP PTI
[ 4767.947967] CPU: 0 PID: 0 Comm: swapper/0
[ 4767.947968] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-20181220_000000-szxrtosci10000 04/01/2014
[ 4767.947972] RIP: 0010:kcs_event+0x3c2/0x890 [ipmi_si]
[ 4767.947974] Code: 74 0e 48 8b 7b 08 31 f6 48 8b 07 e8 98 4f 44 cd 83 bb 24 01
[ 4767.947975] RSP: 0018:fffffe0000007658 EFLAGS: 00010046
[ 4767.947976] RAX: 000000000c7c5ff0 RBX: ffff893e3383a000 RCX: 0000000000000000
[ 4767.947976] RDX: 0000000000000ca2 RSI: 0000000000000000 RDI: ffff893e2fdf6e40
[ 4767.947977] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000a35
[ 4767.947978] R10: 0000000000000002 R11: 0000000000000006 R12: 0000000000000000
[ 4767.947978] R13: fffffe0000007b28 R14: ffff893e34bd0000 R15: 0000000000000000
[ 4767.947979] FS: 0000000000000000(0000) GS:ffff893e3ec00000(0000) knlGS:0000000000000000
[ 4767.947980] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4767.947981] CR2: ffff893e40000000 CR3: 000000013b20a002 CR4: 00000000003606f0
[ 4767.947987] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 4767.947988] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 4767.947988] Call Trace:
[ 4767.947991] <NMI>
[ 4767.947994] smi_event_handler+0x62/0x660 [ipmi_si]
[ 4767.947997] flush_messages+0x10/0x40 [ipmi_si]
[ 4767.948001] ipmi_panic_request_and_wait+0xf5/0x100 [ipmi_msghandler]
[ 4767.948005] ? symbol_string+0x5a/0x90
[ 4767.948007] ? dummy_smi_done_handler+0x10/0x10 [ipmi_msghandler]
[ 4767.948011] ? kvm_sched_clock_read+0xd/0x20
[ 4767.948014] ? sched_clock+0x5/0x10
[ 4767.948017] ? sched_clock_cpu+0xc/0xa0
[ 4767.948019] ? kvm_sched_clock_read+0xd/0x20
[ 4767.948020] ? sched_clock+0x5/0x10
[ 4767.948022] ? sched_clock_cpu+0xc/0xa0
[ 4767.948026] ? log_store+0x278/0x2c0
[ 4767.948027] ? kvm_sched_clock_read+0xd/0x20
[ 4767.948029] ? sched_clock+0x5/0x10
[ 4767.948030] ? sched_clock_cpu+0xc/0xa0
[ 4767.948032] ? log_store+0x278/0x2c0
[ 4767.948034] ? vprintk_emit+0x1dd/0x470
[ 4767.948035] ? vprintk_emit+0x234/0x470
[ 4767.948039] ? secondary_startup_64+0xb7/0xc0
[ 4767.948040] ? vprintk_deferred+0x3a/0x40
[ 4767.948042] ? kvm_sched_clock_read+0xd/0x20
[ 4767.948043] ? sched_clock+0x5/0x10
[ 4767.948045] ? sched_clock_cpu+0xc/0xa0
[ 4767.948046] ? log_store+0x278/0x2c0
[ 4767.948048] ? vprintk_emit+0x1dd/0x470
[ 4767.948049] ? vprintk_emit+0x234/0x470
[ 4767.948051] ? vprintk_deferred+0x3a/0x40
[ 4767.948053] ? printk+0x52/0x6e
[ 4767.948055] ? ipmi_addr_length+0x40/0x40 [ipmi_msghandler]
[ 4767.948057] ? panic_event+0x1d4/0x3e0 [ipmi_msghandler]
[ 4767.948059] panic_event+0x1d4/0x3e0 [ipmi_msghandler]
[ 4767.948062] ? vprintk_deferred+0x3a/0x40
[ 4767.948063] ? printk+0x52/0x6e
[ 4767.948065] ? cpumask_next+0x17/0x20
[ 4767.948067] notifier_call_chain+0x47/0x70
[ 4767.948070] panic+0x17d/0x2c2
[ 4767.948075] mce_panic+0x216/0x240
[ 4767.948077] do_machine_check+0xccd/0xdb0
[ 4767.948082] ? native_safe_halt+0xe/0x10
[ 4767.948086] raise_exception+0x47/0xb0 [mce_inject]
[ 4767.948089] ? __intel_pmu_enable_all+0x47/0x80
[ 4767.948092] ? native_apic_msr_write+0x27/0x30
[ 4767.948093] ? intel_pmu_handle_irq+0x10d/0x160
[ 4767.948095] mce_raise_notify+0x62/0x70 [mce_inject]
[ 4767.948097] ? raise_local+0xc0/0xc0 [mce_inject]
[ 4767.948100] nmi_handle+0x63/0x110
[ 4767.948103] default_do_nmi+0x4e/0x100
[ 4767.948105] do_nmi+0x12c/0x190
[ 4767.948107] end_repeat_nmi+0x16/0x6a

Call Trace:
crash> bt -a
PID: 0 TASK: ffffffff91c12780 CPU: 0 COMMAND: "swapper/0"
#0 [fffffe0000007ba0] panic at ffffffff90ab2e4b
#1 [fffffe0000007c28] mce_panic at ffffffff90a37ec6
#2 [fffffe0000007c70] do_machine_check at ffffffff90a391ad
#3 [fffffe0000007d80] raise_exception at ffffffffc0642117 [mce_inject]
#4 [fffffe0000007e48] mce_raise_notify at ffffffffc0642a92 [mce_inject]
#5 [fffffe0000007e58] nmi_handle at ffffffff90a21c73
#6 [fffffe0000007eb0] default_do_nmi at ffffffff90a2213e
#7 [fffffe0000007ed0] do_nmi at ffffffff90a2231c
#8 [fffffe0000007ef0] end_repeat_nmi at ffffffff914016b4
[exception RIP: native_safe_halt+14]
RIP: ffffffff9127223e RSP: ffffffff91c03e90 RFLAGS: 00000246
RAX: ffffffff91271f30 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R8: 00000031237ac86a R9: 0000000000000001
R10: ffff9f7c01397b88 R11: 0000000002a3fabf R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
--- <NMI exception stack> ---
#9 [ffffffff91c03e90] native_safe_halt at ffffffff9127223e
#10 [ffffffff91c03e90] default_idle at ffffffff91271f4a
#11 [ffffffff91c03eb0] do_idle at ffffffff90ae959a
#12 [ffffffff91c03ef0] cpu_startup_entry at ffffffff90ae981f
#13 [ffffffff91c03f10] start_kernel at ffffffff9219b206
#14 [ffffffff91c03f50] secondary_startup_64 at ffffffff90a000e7

PID: 0 TASK: ffff8b06c77dc740 CPU: 3 COMMAND: "swapper/3"
[exception RIP: port_outb+17]
RIP: ffffffffc035f1a1 RSP: ffff8b06fad83e90 RFLAGS: 00000002
RAX: 0000000000000000 RBX: ffff8b06f08bec00 RCX: 0000000000000010
RDX: 0000000000000ca2 RSI: 0000000000000000 RDI: ffff8b06f0bd5e40
RBP: 0000000000000001 R8: ffff8b06fad80080 R9: ffff8b06fad84000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8b06fad83f54 R14: 0000000000000000 R15: 0000000000000000
CS: 0010 SS: 0018
#0 [ffff8b06fad83e90] kcs_event at ffffffffc035c2c7 [ipmi_si]
#1 [ffff8b06fad83eb0] smi_event_handler at ffffffffc035aa3f [ipmi_si]
#2 [ffff8b06fad83ee8] ipmi_si_irq_handler at ffffffffc035b0cc [ipmi_si]
#3 [ffff8b06fad83f08] __handle_irq_event_percpu at ffffffff9571dfc0
#4 [ffff8b06fad83f48] handle_irq_event_percpu at ffffffff9571e140
#5 [ffff8b06fad83f70] handle_irq_event at ffffffff9571e1b6
#6 [ffff8b06fad83f90] handle_fasteoi_irq at ffffffff95721b42
#7 [ffff8b06fad83fb0] handle_irq at ffffffff956209e8
#8 [ffff8b06fad83fc0] do_IRQ at ffffffff96001ee9
--- <IRQ stack> ---
#9 [fffffe0000088b98] ret_from_intr at ffffffff96000a8f
[exception RIP: delay_tsc+52]
RIP: ffffffff95e5fb64 RSP: fffffe0000088c48 RFLAGS: 00000287
RAX: 000023fb5edf4b14 RBX: 00000000003e0451 RCX: 000023fb5edf4798
RDX: 000000000000037c RSI: 0000000000000003 RDI: 000000000000095b
RBP: fffffe0000088cc0 R8: 0000000000000004 R9: fffffe0000088c5c
R10: ffffffff96a05ae0 R11: 0000000000000000 R12: fffffe0000088cb0
R13: 0000000000000001 R14: fffffe0000088ef8 R15: ffffffff9666a2f0
ORIG_RAX: ffffffffffffffd9 CS: 0010 SS: 0018
#10 [fffffe0000088c48] wait_for_panic at ffffffff95637c6c
#11 [fffffe0000088c58] mce_timed_out at ffffffff95637f5d
#12 [fffffe0000088c70] do_machine_check at ffffffff95638db4
#13 [fffffe0000088d80] raise_exception at ffffffffc05b6117 [mce_inject]
#14 [fffffe0000088e48] mce_raise_notify at ffffffffc05b6a92 [mce_inject]
#15 [fffffe0000088e58] nmi_handle at ffffffff95621c73
#16 [fffffe0000088eb0] default_do_nmi at ffffffff9562213e
#17 [fffffe0000088ed0] do_nmi at ffffffff9562231c
#18 [fffffe0000088ef0] end_repeat_nmi at ffffffff960016b4
[exception RIP: native_safe_halt+14]
RIP: ffffffff95e7223e RSP: ffffa222c06a3eb0 RFLAGS: 00000246
RAX: ffffffff95e71f30 RBX: 0000000000000003 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000083 RDI: 0000000000000000
RBP: 0000000000000003 R8: 00000018cf7cd9a0 R9: 0000000000000001
R10: 0000000000000400 R11: 00000000000003fb R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
--- <NMI exception stack> ---
#19 [ffffa222c06a3eb0] native_safe_halt at ffffffff95e7223e
#20 [ffffa222c06a3eb0] default_idle at ffffffff95e71f4a
#21 [ffffa222c06a3ed0] do_idle at ffffffff956e959a
#22 [ffffa222c06a3f10] cpu_startup_entry at ffffffff956e981f
#23 [ffffa222c06a3f30] start_secondary at ffffffff9564e697
#24 [ffffa222c06a3f50] secondary_startup_64 at ffffffff956000e7

Fixes: e45361d73 ("Factor out message flushing procedure")
Signed-off-by: Feilong Lin <linfeilong@xxxxxxxxxx>
Signed-off-by: Wu Bo <wubo40@xxxxxxxxxx>
---
drivers/char/ipmi/ipmi_si_intf.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 77b8d55..44ba9b6 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -882,16 +882,19 @@ static void flush_messages(void *send_info)
{
struct smi_info *smi_info = send_info;
enum si_sm_result result;
+ unsigned long flags = 0;
+ int time = 0;

- /*
- * Currently, this function is called only in run-to-completion
- * mode. This means we are single-threaded, no need for locks.
- */
- result = smi_event_handler(smi_info, 0);
- while (result != SI_SM_IDLE) {
- udelay(SI_SHORT_TIMEOUT_USEC);
- result = smi_event_handler(smi_info, SI_SHORT_TIMEOUT_USEC);
- }
+restart:
+ if (!spin_trylock_irqsave(&smi_info->si_lock, flags))
+ return;
+ result = smi_event_handler(smi_info, time);
+ spin_unlock_irqrestore(&smi_info->si_lock, flags);
+ if (result != SI_SM_IDLE) {
+ udelay(SI_SHORT_TIMEOUT_USEC);
+ time = SI_SHORT_TIMEOUT_USEC;
+ goto restart;
+ }
}

static void sender(void *send_info,
--
1.8.3.1

Next message: Borislav Petkov: "Re: [PATCH v38 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE"
Previous message: Jason Yan: "Re: [PATCH -next] scsi: libsas: simplify the return expression of sas_discover_* functions"
Next in thread: Corey Minyard: "Re: [RFC PATCH V2] ipmi: ssif: Fix out of bounds in write_next_byte()"
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