sorry, there will be more commits available. c7486104a5ce x86/mce: Fix set_mce_nospec() to avoid #GP fault
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1774366 Title: Fix MCE handling for user access of poisoned device-dax mapping Status in intel: Triaged Status in linux package in Ubuntu: Fix Committed Status in linux source package in Cosmic: Fix Committed Bug description: Description: Customer reports: — We've tried the ndctl error injection. Now the error injection is successful. But we have a couple of questions related with the poisoned block. Here are some tests/steps that I did: 1. I mmap the first 10GB of /dev/dax13.0 to virtual address space and inject an error at offset 1GB (block offset should be 1GB/512bytes = 2097152) which seems fine: [root@scaqae09celadm13 wning]# ndctl inject-error --uninject --block=2097152 --count=1 namespace13.0 Warning: Un-injecting previously injected errors here will not cause the kernel to 'forget' its badblock entries. Those have to be cleared through the normal process of writing the affected blocks { "dev":"namespace13.0", "mode":"dax", "size":518967525376, "uuid":"0738c8bd-3b3f-4989-9d0e-0e9c6006c810", "chardev":"dax13.0", "numa_node":0, "badblock_count":1, "badblocks":[ { "offset":2097152, "length":1, "dimms":[ "nmem1" ] } ] } 2. In my test program, I just try to read every address of the first 10GB. At the first time, when I read the offset 1GB, I got the SIGBUS error, but in the sinfo struct of signal handler, the failed address is NULL and signal code is 128 which seems incorrect. But then if we run again, the unit test gets stuck here: rt_sigaction(SIGBUS, {0x400dd2, [], SA_RESTORER|SA_SIGINFO, 0x7fb5cf839270} , NULL, 8) = 0 And here is the output of log messages: Apr 3 14:39:23 scaqae09celadm13 kernel: mce: Uncorrected hardware memory error in user-access at 952b200000 Apr 3 14:51:11 scaqae09celadm13 kernel: mce: Uncorrected hardware memory error in user-access at 94eb300000 Apr 3 14:51:11 scaqae09celadm13 kernel: mce_notify_irq: 48 callbacks suppressed Apr 3 14:51:11 scaqae09celadm13 kernel: mce: [Hardware Error]: Machine check events logged Apr 3 14:51:11 scaqae09celadm13 kernel: Memory failure: 0x94eb300: reserved kernel page still referenced by 1 users Apr 3 14:51:11 scaqae09celadm13 kernel: Memory failure: 0x94eb300: recovery action for reserved kernel page: Failed Apr 3 14:51:11 scaqae09celadm13 kernel: mce: Memory error not recovered The program I use is (simple do memcpy and directly read from the target address): for (i = 0; i < DAX_MAPPING_SIZE; i++) // DAX_MAPPING_SIZE is 10G { total += peek(buf + i); } char peek(void *addr) { char temp[128]; memcpy(temp, addr, 1); return *(char *)addr; } May I ask do we missed steps in triggering the SIGBUS error? Target Kernel: 4.19 Target Release: 18.10 To manage notifications about this bug go to: https://bugs.launchpad.net/intel/+bug/1774366/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
