Re: [PATCH] powerpc/eeh: Disable EEH stack dump by default
From: Andrew Donnellan <hidden>
Date: 2017-09-20 05:54:54
On 20/09/17 00:25, Jose Ricardo Ziviani wrote:
Today, each EEH causes a stack dump to be printed in the logs. In production environment it's not quite necessary. Thus, this patch adds a new command line argument in order to enable the stack dump for debugging purposes. For example, instead of the following: [ 131.778661] EEH: Frozen PHB#2-PE#fd detected [ 131.778672] EEH: PE location: N/A, PHB location: N/A [ 131.778677] CPU: 21 PID: 10098 Comm: lspci Not tainted ... [ 131.778680] Call Trace: [ 131.778686] [c0000003a140bab0] [c000000000beb58c] dump_stack+... <snip ~10 lines> [ 131.778770] EEH: Detected PCI bus error on PHB#2-PE#fd [ 131.778775] EEH: This PCI device has failed 1 times in the last hour ... we will have this by default: [12777.175880] EEH: Frozen PHB#2-PE#fd detected [12777.175893] EEH: PE location: N/A, PHB location: N/A [12777.175922] EEH: Detected PCI bus error on PHB#2-PE#fd [12777.175931] EEH: This PCI device has failed 2 times in the last hour ... Signed-off-by: Jose Ricardo Ziviani <redacted>
As someone who's had to debug far too many EEH-related bugs, I'd really prefer if this remained as is. Andrew
quoted hunk ↗ jump to hunk
--- arch/powerpc/kernel/eeh.c | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-)diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c index 9e81678..4336c3b1 100644 --- a/arch/powerpc/kernel/eeh.c +++ b/arch/powerpc/kernel/eeh.c@@ -157,6 +157,19 @@ static int __init eeh_setup(char *str) __setup("eeh=", eeh_setup); /* + * It's not necessary to dump the stack trace when an EEH occours + * in the production environment. For debugging, the command line + * option "enable_eeh_stacktrace" brings the stack dump back + */ +static bool eeh_show_stacktrace; +static int __init enable_eeh_stacktrace(char *p) +{ + eeh_show_stacktrace = true; + return 0; +} +early_param("enable_eeh_stacktrace", enable_eeh_stacktrace); + +/* * This routine captures assorted PCI configuration space data * for the indicated PCI device, and puts them into a buffer * for RTAS error logging.@@ -407,7 +420,10 @@ static int eeh_phb_check_failure(struct eeh_pe *pe) pr_err("EEH: PHB#%x failure detected, location: %s\n", phb_pe->phb->global_number, eeh_pe_loc_get(phb_pe)); - dump_stack(); + + if (eeh_show_stacktrace) + dump_stack(); + eeh_send_failure_event(phb_pe); return 1;@@ -504,7 +520,9 @@ int eeh_dev_check_failure(struct eeh_dev *edev) eeh_driver_name(dev), eeh_pci_name(dev)); printk(KERN_ERR "EEH: Might be infinite loop in %s driver\n", eeh_driver_name(dev)); - dump_stack(); + + if (eeh_show_stacktrace) + dump_stack(); } goto dn_unlock; }@@ -572,7 +590,9 @@ int eeh_dev_check_failure(struct eeh_dev *edev) pe->phb->global_number, pe->addr); pr_err("EEH: PE location: %s, PHB location: %s\n", eeh_pe_loc_get(pe), eeh_pe_loc_get(phb_pe)); - dump_stack(); + + if (eeh_show_stacktrace) + dump_stack(); eeh_send_failure_event(pe);
-- Andrew Donnellan OzLabs, ADL Canberra andrew.donnellan@au1.ibm.com IBM Australia Limited