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* [BUG][powerpc] OOPs: Kernel access of bad area during zram swap write - kswapd0 crash
@ 2025-04-20 20:41 Misbah Anjum N
  2025-04-21  3:49 ` Ritesh Harjani
  0 siblings, 1 reply; 6+ messages in thread
From: Misbah Anjum N @ 2025-04-20 20:41 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: maddy, mpe, npiggin, christophe.leroy, naveen, linux-kernel

Bug Description:
When running Avocado-VT based functional tests on KVM guest, the system 
encounters a
kernel panic and crash during memory reclaim activity when zram is 
actively used for
swap. The crash occurs in the kswapd0 kernel thread during what appears 
to be a write
operation to zram.


Steps to Reproduce:
1. Compile Upstream Kernel on LPAR
2. Compile Qemu, Libvirt for KVM Guest
3. Run Functional tests on KVM guest using Avocado-VT Regression Bucket
     a. Clone: git clone https://github.com/lop-devops/tests.git
     b. Setup: python3 avocado-setup.py --bootstrap --enable-kvm 
--install-deps
     c. Add guest in folder: tests/data/avocado-vt/images/
     d. Run: python3 avocado-setup.py --run-suite guest_regression 
--guest-os\
             <Guest-name> --only-filter 'virtio_scsi virtio_net qcow2'\
             --no-download

The bug is reproducible when Avocado-VT Regression bucket is executed 
which
consists of series of functional tp-libvirt tests performed on the KVM 
guest in the
following order: cpu, memory, network, storage and hotplug (disk, change 
media,
libvirt_mem), etc.
Whilst execution, the system crashes during test:
io-github-autotest-libvirt.libvirt_mem.positive_test.mem_basic.cold_plug_discard
Note: This does not appear to be caused by a single test, but by 
cumulative
operations during the test sequence.


Environment Details:
     Kernel: 6.15.0-rc1-g521d54901f98
     Reproducible with: 6.15.0-rc2-gf3a2e2a79c9d
     Platform: IBM POWER10 LPAR (ppc64le)
     Distro: Fedora42
     RAM: 64GB
     CPUs: 80
     Qemu: 9.2.93 (v10.0.0-rc3-10-g8bdd3a0308)
     Libvirt: 11.3.0


System Memory State:
     # free -mh
                     total        used        free      shared  
buff/cache   available
         Mem:            61Gi       3.0Gi        25Gi        11Mi        
33Gi        58Gi
         Swap:          8.0Gi          0B       8.0Gi
     # zramctl
         NAME       ALGORITHM DISKSIZE DATA COMPR TOTAL STREAMS 
MOUNTPOINT
         /dev/zram0 lzo-rle         8G  64K  222B  128K         [SWAP]
     # swapon --show
         NAME       TYPE      SIZE USED PRIO
         /dev/zram0 partition   8G   0B  100


Call Trace:
[180060.602200] BUG: Unable to handle kernel data access on read at 
0xc00800000a1b0000
[180060.602219] Faulting instruction address: 0xc000000000175670
[180060.602224] Oops: Kernel access of bad area, sig: 11 [#1]
[180060.602227] LE PAGE_SIZE=64K MMU=Radix  SMP NR_CPUS=2048 NUMA 
pSeries
[180060.602232] Modules linked in: dm_thin_pool dm_persistent_data 
dm_bio_prison dm_zero
dm_snapshot dm_bufio nfsv4 dns_resolver nfs netfs vfat fat openvswitch 
nf_conncount psample
act_police sch_ingress cls_fw sch_sfq xt_set ip_set_hash_ip ip_set ext4 
crc16 mbcache jbd2
target_core_pscsi target_core_file target_core_iblock ebt_arp ebt_ip 
xt_sctp xt_conntrack
xt_dscp br_netfilter nft_meta_bridge xt_physdev nft_compat 
iscsi_target_mod target_core_user
target_core_mod nvram rpcsec_gss_krb5 binfmt_misc vhost_net vhost 
vhost_iotlb tap tun kvm_hv
kvm nft_masq nft_ct nft_reject_ipv4 nf_reject_ipv4 nft_reject act_csum 
cls_u32 sch_htb
nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 
nf_tables bridge stp llc
rpcrdma rdma_cm iw_cm ib_cm ib_core bonding rfkill nfsd auth_rpcgss 
nfs_acl lockd grace
pseries_rng vmx_crypto drm loop drm_panel_orientation_quirks nfnetlink 
vsock_loopback
vmw_vsock_virtio_transport_common vsock zram xfs dm_service_time sd_mod 
ibmvscsi ibmveth
scsi_transport_srp ipr btrfs blake2b_generic xor
[180060.602306]  raid6_pq zstd_compress sunrpc dm_mirror dm_region_hash 
dm_log be2iscsi bnx2i
cnic uio cxgb4i cxgb4 tls libcxgbi libcxgb qla4xxx iscsi_boot_sysfs 
iscsi_tcp libiscsi_tcp
libiscsi scsi_transport_iscsi dm_multipath fuse dm_mod [last unloaded: 
ipmi_msghandler]
[180060.602345] CPU: 68 UID: 0 PID: 465 Comm: kswapd0 Kdump: loaded Not 
tainted
6.15.0-rc1-g521d54901f98 #1 VOLUNTARY
[180060.602351] Hardware name: IBM,9080-HEX POWER10 (architected) 
0x800200 0xf000006 of:IBM,FW1060.21
(NH1060_078) hv:phyp pSeries
[180060.602355] NIP:  c000000000175670 LR: c0000000006d96b4 CTR: 
01fffffffffffc05
[180060.602358] REGS: c0000000a5a56da0 TRAP: 0300   Not tainted  
(6.15.0-rc1-g521d54901f98)
[180060.602362] MSR:  8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE>  CR: 
44042880  XER: 20040001
[180060.602370] CFAR: c0000000001756c8 DAR: c00800000a1b0000 DSISR: 
40000000 IRQMASK: 0
[180060.602370] GPR00: 000000000e000000 c0000000a5a57040 
c0000000017a8100 c000000d34cefd00
[180060.602370] GPR04: c00800000a1affe8 fffffffffffffffa 
01ffffffffffffff 03ffffff2cb33000
[180060.602370] GPR08: 0000000080000000 0000000000000010 
0000000000000020 0000000000000030
[180060.602370] GPR12: 0000000000000040 c000000ffde34300 
0000000000000050 0000000000000060
[180060.602370] GPR16: 0000000000000070 5deadbeef0000122 
0000000101124ad9 0000000000018028
[180060.602370] GPR20: 0000000000c01400 c0000000a5a574b0 
0000000000010000 0000000000000051
[180060.602370] GPR24: c000000002be02f8 c00c000003ef7380 
c00800000a190000 c0000001054dbbe0
[180060.602370] GPR28: c00c0000034d3340 00000000000002d8 
fffffffffffffffa c0000001054dbbb0
[180060.602410] NIP [c000000000175670] memcpy_power7+0x670/0x7d0
[180060.602417] LR [c0000000006d96b4] zs_obj_write+0x224/0x290
[180060.602422] Call Trace:
[180060.602424] [c0000000a5a57040] [c000000000175274] 
memcpy_power7+0x274/0x7d0 (unreliable)
[180060.602430] [c0000000a5a57140] [c0000000006d96b4] 
zs_obj_write+0x224/0x290
[180060.602435] [c0000000a5a571b0] [c008000009174a50] 
zram_write_page+0x298/0x530 [zram]
[180060.602442] [c0000000a5a57260] [c008000009174ff4] 
zram_bio_write+0x1cc/0x2b0 [zram]
[180060.602446] [c0000000a5a57310] [c0000000009323ac] 
__submit_bio+0x15c/0x340
[180060.602451] [c0000000a5a573a0] [c000000000932614] 
__submit_bio_noacct+0x84/0x240
[180060.602456] [c0000000a5a57410] [c000000000926d34] 
submit_bio_wait+0x74/0x110
[180060.602461] [c0000000a5a57480] [c00000000065ab5c] 
swap_writepage_bdev_sync+0xec/0x140
[180060.602467] [c0000000a5a57540] [c00000000065b90c] 
swap_writepage+0x21c/0x2b0
[180060.602471] [c0000000a5a57570] [c0000000005ada30] 
shmem_writepage+0x4a0/0x640
[180060.602476] [c0000000a5a57630] [c00000000059d700] 
pageout+0x1d0/0x440
[180060.602480] [c0000000a5a57850] [c00000000059eafc] 
shrink_folio_list+0x7cc/0x1150
[180060.602484] [c0000000a5a57aa0] [c0000000005a0b38] 
shrink_inactive_list+0x278/0x6f0
[180060.602488] [c0000000a5a57b70] [c0000000005a12a0] 
shrink_lruvec+0x2f0/0x470
[180060.602492] [c0000000a5a57c80] [c0000000005a16f4] 
shrink_node_memcgs+0x2d4/0x360
[180060.602497] [c0000000a5a57d00] [c0000000005a183c] 
shrink_node+0xbc/0x4e0
[180060.602500] [c0000000a5a57d80] [c0000000005a24e0] 
balance_pgdat+0x4b0/0xa00
[180060.602504] [c0000000a5a57ef0] [c0000000005a2b50] kswapd+0x120/0x260
[180060.602508] [c0000000a5a57f80] [c00000000026ea68] 
kthread+0x168/0x180
[180060.602512] [c0000000a5a57fe0] [c00000000000df98] 
start_kernel_thread+0x14/0x18
[180060.602516] Code: 39c00050 39e00060 3a000070 7cc903a6 60000000 
60000000 60000000 60000000
7ce020ce 1107042b 7cc448ce 11263c2b <7ca450ce> 1145342b 7c8458ce 
11642c2b
[180060.602529] ---[ end trace 0000000000000000 ]---


Crash Utility Output:
# crash /home/kvmci/linux/vmlinux vmcore
crash 8.0.6-4.fc42

       KERNEL: /home/kvmci/linux/vmlinux  [TAINTED]
     DUMPFILE: vmcore  [PARTIAL DUMP]
         CPUS: 80
         DATE: Wed Dec 31 18:00:00 CST 1969
       UPTIME: 2 days, 02:01:00
LOAD AVERAGE: 0.72, 0.66, 0.64
        TASKS: 1249
     NODENAME: ***
      RELEASE: 6.15.0-rc1-g521d54901f98
      VERSION: #1 SMP Wed Apr  9 05:13:03 CDT 2025
      MACHINE: ppc64le  (3450 Mhz)
       MEMORY: 64 GB
        PANIC: "Oops: Kernel access of bad area, sig: 11 [#1]" (check log 
for details)
          PID: 465
      COMMAND: "kswapd0"
         TASK: c000000006067d80  [THREAD_INFO: c000000006067d80]
          CPU: 68
        STATE: TASK_RUNNING (PANIC)

crash> bt
PID: 465      TASK: c000000006067d80  CPU: 68   COMMAND: "kswapd0"
  R0:  000000000e000000    R1:  c0000000a5a57040    R2:  c0000000017a8100
  R3:  c000000d34cefd00    R4:  c00800000a1affe8    R5:  fffffffffffffffa
  R6:  01ffffffffffffff    R7:  03ffffff2cb33000    R8:  0000000080000000
  R9:  0000000000000010    R10: 0000000000000020    R11: 0000000000000030
  R12: 0000000000000040    R13: c000000ffde34300    R14: 0000000000000050
  R15: 0000000000000060    R16: 0000000000000070    R17: 5deadbeef0000122
  R18: 0000000101124ad9    R19: 0000000000018028    R20: 0000000000c01400
  R21: c0000000a5a574b0    R22: 0000000000010000    R23: 0000000000000051
  R24: c000000002be02f8    R25: c00c000003ef7380    R26: c00800000a190000
  R27: c0000001054dbbe0    R28: c00c0000034d3340    R29: 00000000000002d8
  R30: fffffffffffffffa    R31: c0000001054dbbb0
  NIP: c000000000175670    MSR: 8000000002009033    OR3: c0000000001756c8
  CTR: 01fffffffffffc05    LR:  c0000000006d96b4    XER: 0000000020040001
  CCR: 0000000044042880    MQ:  0000000000000000    DAR: c00800000a1b0000
  DSISR: 0000000040000000     Syscall Result: 0000000000000000
  [NIP  : memcpy_power7+1648]
  [LR   : zs_obj_write+548]
  #0 [c0000000a5a56c50] crash_kexec at c00000000037f268
  #1 [c0000000a5a56c80] oops_end at c00000000002b678
  #2 [c0000000a5a56d00] __bad_page_fault at c00000000014f348
  #3 [c0000000a5a56d70] data_access_common_virt at c000000000008be0
  #4 [c0000000a5a57040] memcpy_power7 at c000000000175274
  #5 [c0000000a5a57140] zs_obj_write at c0000000006d96b4
  #6 [c0000000a5a571b0] zram_write_page at c008000009174a50 [zram]
  #7 [c0000000a5a57260] zram_bio_write at c008000009174ff4 [zram]
  #8 [c0000000a5a57310] __submit_bio at c0000000009323ac
  #9 [c0000000a5a573a0] __submit_bio_noacct at c000000000932614
#10 [c0000000a5a57410] submit_bio_wait at c000000000926d34
#11 [c0000000a5a57480] swap_writepage_bdev_sync at c00000000065ab5c
#12 [c0000000a5a57540] swap_writepage at c00000000065b90c
#13 [c0000000a5a57570] shmem_writepage at c0000000005ada30
#14 [c0000000a5a57630] pageout at c00000000059d700
#15 [c0000000a5a57850] shrink_folio_list at c00000000059eafc
#16 [c0000000a5a57aa0] shrink_inactive_list at c0000000005a0b38
#17 [c0000000a5a57b70] shrink_lruvec at c0000000005a12a0
#18 [c0000000a5a57c80] shrink_node_memcgs at c0000000005a16f4
#19 [c0000000a5a57d00] shrink_node at c0000000005a183c
#20 [c0000000a5a57d80] balance_pgdat at c0000000005a24e0
#21 [c0000000a5a57ef0] kswapd at c0000000005a2b50
#22 [c0000000a5a57f80] kthread at c00000000026ea68
#23 [c0000000a5a57fe0] start_kernel_thread at c00000000000df98


Thank you,
Misbah Anjum N

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [BUG][powerpc] OOPs: Kernel access of bad area during zram swap write - kswapd0 crash
  2025-04-20 20:41 [BUG][powerpc] OOPs: Kernel access of bad area during zram swap write - kswapd0 crash Misbah Anjum N
@ 2025-04-21  3:49 ` Ritesh Harjani
  2025-04-28  5:09   ` Misbah Anjum N
  2025-05-06  5:39   ` Misbah Anjum N
  0 siblings, 2 replies; 6+ messages in thread
From: Ritesh Harjani @ 2025-04-21  3:49 UTC (permalink / raw)
  To: Misbah Anjum N, linuxppc-dev, linux-mm
  Cc: maddy, mpe, npiggin, christophe.leroy, naveen, linux-kernel


++ linux-mm

Misbah Anjum N <misanjum@linux.ibm.com> writes:

> Bug Description:
> When running Avocado-VT based functional tests on KVM guest, the system 
> encounters a
> kernel panic and crash during memory reclaim activity when zram is 
> actively used for
> swap. The crash occurs in the kswapd0 kernel thread during what appears 
> to be a write
> operation to zram.
>
>
> Steps to Reproduce:
> 1. Compile Upstream Kernel on LPAR
> 2. Compile Qemu, Libvirt for KVM Guest
> 3. Run Functional tests on KVM guest using Avocado-VT Regression Bucket
>      a. Clone: git clone https://github.com/lop-devops/tests.git
>      b. Setup: python3 avocado-setup.py --bootstrap --enable-kvm 
> --install-deps
>      c. Add guest in folder: tests/data/avocado-vt/images/
>      d. Run: python3 avocado-setup.py --run-suite guest_regression 
> --guest-os\
>              <Guest-name> --only-filter 'virtio_scsi virtio_net qcow2'\
>              --no-download
>
> The bug is reproducible when Avocado-VT Regression bucket is executed 
> which
> consists of series of functional tp-libvirt tests performed on the KVM 
> guest in the
> following order: cpu, memory, network, storage and hotplug (disk, change 
> media,
> libvirt_mem), etc.
> Whilst execution, the system crashes during test:
> io-github-autotest-libvirt.libvirt_mem.positive_test.mem_basic.cold_plug_discard
> Note: This does not appear to be caused by a single test, but by 
> cumulative
> operations during the test sequence.
>
>
> Environment Details:
>      Kernel: 6.15.0-rc1-g521d54901f98
>      Reproducible with: 6.15.0-rc2-gf3a2e2a79c9d


Looks like the issue is happening on 6.15-rc2. Did git bisect revealed a
faulty commit?


>      Platform: IBM POWER10 LPAR (ppc64le)
>      Distro: Fedora42
>      RAM: 64GB
>      CPUs: 80
>      Qemu: 9.2.93 (v10.0.0-rc3-10-g8bdd3a0308)
>      Libvirt: 11.3.0
>
>
> System Memory State:
>      # free -mh
>                      total        used        free      shared  
> buff/cache   available
>          Mem:            61Gi       3.0Gi        25Gi        11Mi        
> 33Gi        58Gi
>          Swap:          8.0Gi          0B       8.0Gi
>      # zramctl
>          NAME       ALGORITHM DISKSIZE DATA COMPR TOTAL STREAMS 
> MOUNTPOINT
>          /dev/zram0 lzo-rle         8G  64K  222B  128K         [SWAP]
>      # swapon --show
>          NAME       TYPE      SIZE USED PRIO
>          /dev/zram0 partition   8G   0B  100
>
>
> Call Trace:
> [180060.602200] BUG: Unable to handle kernel data access on read at 
> 0xc00800000a1b0000
> [180060.602219] Faulting instruction address: 0xc000000000175670
> [180060.602224] Oops: Kernel access of bad area, sig: 11 [#1]
> [180060.602227] LE PAGE_SIZE=64K MMU=Radix  SMP NR_CPUS=2048 NUMA 
> pSeries
> [180060.602232] Modules linked in: dm_thin_pool dm_persistent_data 
> vmw_vsock_virtio_transport_common vsock zram xfs dm_service_time sd_mod 
> [180060.602345] CPU: 68 UID: 0 PID: 465 Comm: kswapd0 Kdump: loaded Not 
> tainted
> 6.15.0-rc1-g521d54901f98 #1 VOLUNTARY
> [180060.602351] Hardware name: IBM,9080-HEX POWER10 (architected) 
> 0x800200 0xf000006 of:IBM,FW1060.21
> (NH1060_078) hv:phyp pSeries
> [180060.602355] NIP:  c000000000175670 LR: c0000000006d96b4 CTR: 
> 01fffffffffffc05
> [180060.602358] REGS: c0000000a5a56da0 TRAP: 0300   Not tainted  
> (6.15.0-rc1-g521d54901f98)
> [180060.602362] MSR:  8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE>  CR: 
> 44042880  XER: 20040001
> [180060.602370] CFAR: c0000000001756c8 DAR: c00800000a1b0000 DSISR: 
> 40000000 IRQMASK: 0
<...>
>
>
> Crash Utility Output:
> # crash /home/kvmci/linux/vmlinux vmcore
> crash 8.0.6-4.fc42
>
>        KERNEL: /home/kvmci/linux/vmlinux  [TAINTED]
>      DUMPFILE: vmcore  [PARTIAL DUMP]
>          CPUS: 80
>          DATE: Wed Dec 31 18:00:00 CST 1969
>        UPTIME: 2 days, 02:01:00
> LOAD AVERAGE: 0.72, 0.66, 0.64
>         TASKS: 1249
>      NODENAME: ***
>       RELEASE: 6.15.0-rc1-g521d54901f98
>       VERSION: #1 SMP Wed Apr  9 05:13:03 CDT 2025
>       MACHINE: ppc64le  (3450 Mhz)
>        MEMORY: 64 GB
>         PANIC: "Oops: Kernel access of bad area, sig: 11 [#1]" (check log 
> for details)
>           PID: 465
>       COMMAND: "kswapd0"
>          TASK: c000000006067d80  [THREAD_INFO: c000000006067d80]
>           CPU: 68
>         STATE: TASK_RUNNING (PANIC)
>
> crash> bt
> PID: 465      TASK: c000000006067d80  CPU: 68   COMMAND: "kswapd0"
>   R0:  000000000e000000    R1:  c0000000a5a57040    R2:  c0000000017a8100
>   R3:  c000000d34cefd00    R4:  c00800000a1affe8    R5:  fffffffffffffffa
>   R6:  01ffffffffffffff    R7:  03ffffff2cb33000    R8:  0000000080000000
>   R9:  0000000000000010    R10: 0000000000000020    R11: 0000000000000030
>   R12: 0000000000000040    R13: c000000ffde34300    R14: 0000000000000050
>   R15: 0000000000000060    R16: 0000000000000070    R17: 5deadbeef0000122
>   R18: 0000000101124ad9    R19: 0000000000018028    R20: 0000000000c01400
>   R21: c0000000a5a574b0    R22: 0000000000010000    R23: 0000000000000051
>   R24: c000000002be02f8    R25: c00c000003ef7380    R26: c00800000a190000
>   R27: c0000001054dbbe0    R28: c00c0000034d3340    R29: 00000000000002d8
>   R30: fffffffffffffffa    R31: c0000001054dbbb0
>   NIP: c000000000175670    MSR: 8000000002009033    OR3: c0000000001756c8
>   CTR: 01fffffffffffc05    LR:  c0000000006d96b4    XER: 0000000020040001
>   CCR: 0000000044042880    MQ:  0000000000000000    DAR: c00800000a1b0000
>   DSISR: 0000000040000000     Syscall Result: 0000000000000000
>   [NIP  : memcpy_power7+1648]
>   [LR   : zs_obj_write+548]
>   #0 [c0000000a5a56c50] crash_kexec at c00000000037f268
>   #1 [c0000000a5a56c80] oops_end at c00000000002b678
>   #2 [c0000000a5a56d00] __bad_page_fault at c00000000014f348
>   #3 [c0000000a5a56d70] data_access_common_virt at c000000000008be0
>   #4 [c0000000a5a57040] memcpy_power7 at c000000000175274
>   #5 [c0000000a5a57140] zs_obj_write at c0000000006d96b4

Looks like zsmalloc new object mapping API being called, which was
merged in rc1?  But let's first confirm from git bisect, unless someone
from linux-mm who knows zsmalloc subsystem better and can point on what
could be going wrong here.


>   #6 [c0000000a5a571b0] zram_write_page at c008000009174a50 [zram]
>   #7 [c0000000a5a57260] zram_bio_write at c008000009174ff4 [zram]
>   #8 [c0000000a5a57310] __submit_bio at c0000000009323ac
>   #9 [c0000000a5a573a0] __submit_bio_noacct at c000000000932614
> #10 [c0000000a5a57410] submit_bio_wait at c000000000926d34
> #11 [c0000000a5a57480] swap_writepage_bdev_sync at c00000000065ab5c
> #12 [c0000000a5a57540] swap_writepage at c00000000065b90c
> #13 [c0000000a5a57570] shmem_writepage at c0000000005ada30
> #14 [c0000000a5a57630] pageout at c00000000059d700
> #15 [c0000000a5a57850] shrink_folio_list at c00000000059eafc
> #16 [c0000000a5a57aa0] shrink_inactive_list at c0000000005a0b38
> #17 [c0000000a5a57b70] shrink_lruvec at c0000000005a12a0
> #18 [c0000000a5a57c80] shrink_node_memcgs at c0000000005a16f4
> #19 [c0000000a5a57d00] shrink_node at c0000000005a183c
> #20 [c0000000a5a57d80] balance_pgdat at c0000000005a24e0
> #21 [c0000000a5a57ef0] kswapd at c0000000005a2b50
> #22 [c0000000a5a57f80] kthread at c00000000026ea68
> #23 [c0000000a5a57fe0] start_kernel_thread at c00000000000df98
>

-ritesh

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [BUG][powerpc] OOPs: Kernel access of bad area during zram swap write - kswapd0 crash
  2025-04-21  3:49 ` Ritesh Harjani
@ 2025-04-28  5:09   ` Misbah Anjum N
  2025-05-06  5:39   ` Misbah Anjum N
  1 sibling, 0 replies; 6+ messages in thread
From: Misbah Anjum N @ 2025-04-28  5:09 UTC (permalink / raw)
  To: Ritesh Harjani
  Cc: christophe.leroy, linux-kernel, linux-mm, linuxppc-dev, maddy,
	mpe, naveen, npiggin

On 2025-04-21 09:19, Ritesh Harjani wrote:

> Looks like the issue is happening on 6.15-rc2. Did git bisect revealed 
> a
> faulty commit?
> 
> Looks like zsmalloc new object mapping API being called, which was
> merged in rc1?  But let's first confirm from git bisect, unless someone
> from linux-mm who knows zsmalloc subsystem better and can point on what
> could be going wrong here.
> 
> -ritesh

Hi,

Regarding the issue, I am currently running tests by removing the 
suspected faulty commit. Unfortunately, git bisect is not feasible in 
this case because recreating the bug requires running the avocado bucket 
for approximately two days. Hence, I am resetting the kernel to the 
commit prior to: 44f76413496ec343da0d8292ceecdcabe3e6ec16 and manually 
running the bucket to come to conclusions.

The commit in question: 44f76413496ec343da0d8292ceecdcabe3e6ec16 
introduces zsmalloc - new object mapping API
More information: 
https://github.com/torvalds/linux/commit/44f76413496ec343da0d8292ceecdcabe3e6ec16

I will update the upstream bug report with this information after 
performing the tests.
Thank you,
Misbah Anjum N

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [BUG][powerpc] OOPs: Kernel access of bad area during zram swap write - kswapd0 crash
  2025-04-21  3:49 ` Ritesh Harjani
  2025-04-28  5:09   ` Misbah Anjum N
@ 2025-05-06  5:39   ` Misbah Anjum N
  2025-05-07  0:33     ` Sergey Senozhatsky
  1 sibling, 1 reply; 6+ messages in thread
From: Misbah Anjum N @ 2025-05-06  5:39 UTC (permalink / raw)
  To: Ritesh Harjani, senozhatsky, yosry.ahmed
  Cc: linuxppc-dev, linux-mm, maddy, mpe, npiggin, christophe.leroy,
	naveen, linux-kernel

Hi,

I am facing this issue even with the latest kernel: 
6.15.0-rc4-g5721cf0b9352
The suspecting commit is: 44f76413496ec343da0d8292ceecdcabe3e6ec16. The 
commit introduces zs_obj_write() function.
Link: 
https://github.com/torvalds/linux/commit/44f76413496ec343da0d8292ceecdcabe3e6ec16

I was not able to reproduce the issue by reverting to the prior commit: 
e27af3f9360ee130b7ab0b274088f92146a0855b
I would like to request assistance in debugging the issue.

Thank you,
Misbah Anjum N

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [BUG][powerpc] OOPs: Kernel access of bad area during zram swap write - kswapd0 crash
  2025-05-06  5:39   ` Misbah Anjum N
@ 2025-05-07  0:33     ` Sergey Senozhatsky
  2025-05-19 18:07       ` Misbah Anjum N
  0 siblings, 1 reply; 6+ messages in thread
From: Sergey Senozhatsky @ 2025-05-07  0:33 UTC (permalink / raw)
  To: Misbah Anjum N
  Cc: Ritesh Harjani, senozhatsky, yosry.ahmed, linuxppc-dev, linux-mm,
	maddy, mpe, npiggin, christophe.leroy, naveen, linux-kernel

Hi,

On (25/05/06 11:09), Misbah Anjum N wrote:
> I am facing this issue even with the latest kernel: 6.15.0-rc4-g5721cf0b9352
> The suspecting commit is: 44f76413496ec343da0d8292ceecdcabe3e6ec16. The
> commit introduces zs_obj_write() function.
> Link: https://github.com/torvalds/linux/commit/44f76413496ec343da0d8292ceecdcabe3e6ec16

Can you try the following fix
https://lore.kernel.org/linux-mm/20250504110650.2783619-1-senozhatsky@chromium.org

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [BUG][powerpc] OOPs: Kernel access of bad area during zram swap write - kswapd0 crash
  2025-05-07  0:33     ` Sergey Senozhatsky
@ 2025-05-19 18:07       ` Misbah Anjum N
  0 siblings, 0 replies; 6+ messages in thread
From: Misbah Anjum N @ 2025-05-19 18:07 UTC (permalink / raw)
  To: Sergey Senozhatsky
  Cc: Ritesh Harjani, yosry.ahmed, linuxppc-dev, linux-mm, maddy, mpe,
	npiggin, christophe.leroy, naveen, linux-kernel

On 2025-05-07 06:03, Sergey Senozhatsky wrote:
> Hi,
> 
> On (25/05/06 11:09), Misbah Anjum N wrote:
>> I am facing this issue even with the latest kernel: 
>> 6.15.0-rc4-g5721cf0b9352
>> The suspecting commit is: 44f76413496ec343da0d8292ceecdcabe3e6ec16. 
>> The
>> commit introduces zs_obj_write() function.
>> Link: 
>> https://github.com/torvalds/linux/commit/44f76413496ec343da0d8292ceecdcabe3e6ec16
> 
> Can you try the following fix
> https://lore.kernel.org/linux-mm/20250504110650.2783619-1-senozhatsky@chromium.org

Hi,

Thank you for the patch. I can confirm that it resolves the issue. After 
applying it, the kernel panic no longer occurs during memory reclaim 
with in my KVM guest testing environment. The Avocado-VT functional 
tests now complete successfully.

Patch:
Author: Sergey Senozhatsky <senozhatsky@chromium.org>
Date:   Sun May 4 20:00:22 2025 +0900
     zsmalloc: don't underflow size calculation in zs_obj_write()

Thank You,
Misbah Anjum N

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2025-05-19 18:07 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-04-20 20:41 [BUG][powerpc] OOPs: Kernel access of bad area during zram swap write - kswapd0 crash Misbah Anjum N
2025-04-21  3:49 ` Ritesh Harjani
2025-04-28  5:09   ` Misbah Anjum N
2025-05-06  5:39   ` Misbah Anjum N
2025-05-07  0:33     ` Sergey Senozhatsky
2025-05-19 18:07       ` Misbah Anjum N

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