Subject: [Bug 204819] New: KASAN still got problems loading some modules at boot

From: [email-masked]
Date: Wed, 11 Sep 2019 22:47:36 +0000

https://bugzilla.kernel.org/show_bug.cgi?id=204819

            Bug ID: 204819
           Summary: KASAN still got problems loading some modules at boot
           Product: Platform Specific/Hardware
           Version: 2.5
    Kernel Version: 5.3-rc8
          Hardware: PPC-32
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: PPC-32
          Assignee: [email-masked]
          Reporter: [email-masked]
        Regression: No

Created attachment 284931
  --> https://bugzilla.kernel.org/attachment.cgi?id=284931&action=edit
dmesg (5.3-rc8, PowerMac G4 DP)

I tried finding a minimal kernel .config for bug #204479 to rule out other
influences.

What I found was, that KASAN shows different BUG: Unable to handle kernel data
access at 0x.......", depending on which module gets loaded/used first, like:

[...]
Sep 12 00:12:09 T600 kernel: BUG: Unable to handle kernel data access at
0xfe205150
Sep 12 00:12:09 T600 kernel: Faulting instruction address: 0xc00261d8
Sep 12 00:12:09 T600 kernel: Oops: Kernel access of bad area, sig: 11 [#1]
Sep 12 00:12:09 T600 kernel: BE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=2 PowerMac
Sep 12 00:12:09 T600 kernel: Modules linked in: sungem_phy(+) usb_common
Sep 12 00:12:09 T600 kernel: CPU: 0 PID: 117 Comm: systemd-udevd Tainted: G    
   W         5.3.0-rc8 #3
Sep 12 00:12:09 T600 kernel: NIP:  c00261d8 LR: c02355c4 CTR: c0236c6c
Sep 12 00:12:09 T600 kernel: REGS: eb7d5ae0 TRAP: 0300   Tainted: G        W   
      (5.3.0-rc8)
Sep 12 00:12:09 T600 kernel: MSR:  00009032 <EE,ME,IR,DR,RI>  CR: 48228828 
XER: 20000000
Sep 12 00:12:09 T600 kernel: DAR: fe205150 DSISR: 0a000000 
                             GPR00: c0236cb0 eb7d5b98 ebbd2320 fe205150
00000000 00000007 c01083dc 00000003 
                             GPR08: e991025c 1e205150 00000000 f1013000
c0236c6c 007d6980 eb7d5eb8 eb7d5eb0 
                             GPR16: f10504c0 00000124 f102a880 f103d000
c010426c c144c480 00000011 eb9ef9a0 
                             GPR24: f102a8dc f102a8e0 f1013000 f102a810
0000002d 00000001 0000003c f1028a80 
Sep 12 00:12:09 T600 kernel: NIP [c00261d8] __memset+0x10/0xc0
Sep 12 00:12:09 T600 kernel: LR [c02355c4] kasan_unpoison_shadow+0x20/0x40
Sep 12 00:12:09 T600 kernel: Call Trace:
Sep 12 00:12:09 T600 kernel: [eb7d5b98] [ee802420] 0xee802420 (unreliable)
Sep 12 00:12:09 T600 kernel: [eb7d5ba8] [c0236cb0]
__asan_register_globals+0x44/0x68
Sep 12 00:12:09 T600 kernel: [eb7d5bc8] [c01083e8] do_init_module+0x134/0x2c4
Sep 12 00:12:09 T600 kernel: [eb7d5bf8] [c010b1b8] load_module+0x2b60/0x2d1c
Sep 12 00:12:09 T600 kernel: [eb7d5df8] [c010b5d8] sys_finit_module+0x100/0x140
Sep 12 00:12:09 T600 kernel: [eb7d5f38] [c001a274] ret_from_syscall+0x0/0x34
Sep 12 00:12:09 T600 kernel: --- interrupt: c00 at 0x24f2c4
                                 LR = 0x43e35c
Sep 12 00:12:09 T600 kernel: Instruction dump:
Sep 12 00:12:09 T600 kernel: 7c062396 7d4021d6 7d080214 7cca3050 90e30000
91030004 7cc33378 4e800020 
Sep 12 00:12:09 T600 kernel: 28050004 418000a0 5084442e 5084801e <90830000>
4d820020 70600003 7ca02a14 
Sep 12 00:12:09 T600 kernel: ---[ end trace 00769ab21374844d ]---
[...]
This changes depending on which modules I build for the kernel. So I suspect
KASAN to still not get the module loading quite right for all modules. At least
on my system (PowerMac G4 DP).

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