On 2023-08-15 06:47, Michael Ellerman wrote:
Joel Stanley <j...@jms.id.au> writes:
On Fri, 7 Jul 2023 at 05:11, Mahesh Salgaonkar <mah...@linux.ibm.com> wrote:

opal_prd_msg_notifier extracts the opal prd message size from the message
header and uses it for allocating opal_prd_msg_queue_item that includes
the correct message size to be copied. However, while running under
CONFIG_FORTIFY_SOURCE=y, it triggers following run-time warning:

[ 6458.234352] memcpy: detected field-spanning write (size 32) of single field "&item->msg" at arch/powerpc/platforms/powernv/opal-prd.c:355 (size 4) [ 6458.234390] WARNING: CPU: 9 PID: 660 at arch/powerpc/platforms/powernv/opal-prd.c:355 opal_prd_msg_notifier+0x174/0x188 [opal_prd]
[...]
[ 6458.234709] NIP [c00800000e0c0e6c] opal_prd_msg_notifier+0x174/0x188 [opal_prd] [ 6458.234723] LR [c00800000e0c0e68] opal_prd_msg_notifier+0x170/0x188 [opal_prd]
[ 6458.234736] Call Trace:
[ 6458.234742] [c0000002acb23c10] [c00800000e0c0e68] opal_prd_msg_notifier+0x170/0x188 [opal_prd] (unreliable) [ 6458.234759] [c0000002acb23ca0] [c00000000019ccc0] notifier_call_chain+0xc0/0x1b0 [ 6458.234774] [c0000002acb23d00] [c00000000019ceac] atomic_notifier_call_chain+0x2c/0x40 [ 6458.234788] [c0000002acb23d20] [c0000000000d69b4] opal_message_notify+0xf4/0x2c0
[...]

Split the copy to avoid false positive run-time warning.

Reported-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
Signed-off-by: Mahesh Salgaonkar <mah...@linux.ibm.com>

I hit this on a box running the Ubuntu 6.2.0-27-generic kernel.

Do we plan on merging this fix?

I thought it was papering over the issue rather than fixing the root
cause.

I'll send a new version, as soon as I can work out how to trigger that
code path.

cheers

Hi, I see this was still not accepted. I was able to trigger this simply by starting the opal-prd userspace daemon.
Restarting the service does not re-trigger the warning, however.

[Wed Nov 15 14:01:06 2023] i2c_dev: i2c /dev entries driver
[Wed Nov 15 14:01:07 2023] ------------[ cut here ]------------
[Wed Nov 15 14:01:07 2023] memcpy: detected field-spanning write (size 32) of single field "&item->msg" at arch/powerpc/platforms/powernv/opal-prd.c:355 (size 4) [Wed Nov 15 14:01:07 2023] WARNING: CPU: 5 PID: 379 at arch/powerpc/platforms/powernv/opal-prd.c:355 0xc008000000640b1c [Wed Nov 15 14:01:07 2023] Modules linked in: i2c_dev loop vhost_net vhost vhost_iotlb tap kvm_hv kvm bridge rpcsec_gss_krb5 auth_rpcgss tun nfsv4 dns_resolver nfs lockd grace sunrpc fscache netfs cfg80211 rfkill 8021q garp mrp stp llc nft_masq nft_chain_nat nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct binfmt_misc nbd wireguard libcurve25519_generic ip6_udp_tunnel udp_tunnel nft_nat nf_tables nfnetlink nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 at24 ast i2c_algo_bit drm_shmem_helper joydev ftdi_sio crct10dif_vpmsum onboard_usb_hub ofpart drm_kms_helper ipmi_powernv rtc_opal ipmi_devintf powernv_flash ipmi_msghandler mtd opal_prd i2c_opal vmx_crypto nvme crc32c_vpmsum tg3 nvme_core ixgbe nvme_common mdio [Wed Nov 15 14:01:07 2023] CPU: 5 PID: 379 Comm: kopald Not tainted 6.5.9-gentoo-dist #1 [Wed Nov 15 14:01:07 2023] Hardware name: T2P9S01 REV 1.01 POWER9 0x4e1203 opal:skiboot-9858186 PowerNV [Wed Nov 15 14:01:07 2023] NIP: c008000000640b1c LR: c008000000640b18 CTR: 0000000000000000 [Wed Nov 15 14:01:07 2023] REGS: c00000000e2339b0 TRAP: 0700 Not tainted (6.5.9-gentoo-dist) [Wed Nov 15 14:01:07 2023] MSR: 9000000000021033 <SF,HV,ME,IR,DR,RI,LE> CR: 44002222 XER: 00000000
[Wed Nov 15 14:01:07 2023] CFAR: c000000000152b10 IRQMASK: 1
GPR00: c008000000640b18 c00000000e233c50 c008000000668100 0000000000000086 GPR04: 00000000ffff7fff c00000000e233a10 c00000000e233a08 0000001ef74d0000 GPR08: 0000000000000027 c000001ef9626d10 0000000000000001 0000000044002222 GPR12: 20646c6569662065 c000001fff7fb400 c0000000001900e8 c00000000e919540 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR24: c00000000e959de0 0000000000000006 0000000000000000 c008000000660290 GPR28: c000000007498410 0000000000000020 c00000000e959de8 c000000007498400
[Wed Nov 15 14:01:07 2023] NIP [c008000000640b1c] 0xc008000000640b1c
[Wed Nov 15 14:01:07 2023] LR [c008000000640b18] 0xc008000000640b18
[Wed Nov 15 14:01:07 2023] Call Trace:
[Wed Nov 15 14:01:07 2023] [c00000000e233c50] [c008000000640b18] 0xc008000000640b18 (unreliable) [Wed Nov 15 14:01:07 2023] [c00000000e233cd0] [c000000000192dd0] notifier_call_chain+0xc0/0x1b0 [Wed Nov 15 14:01:07 2023] [c00000000e233d30] [c000000000192eec] atomic_notifier_call_chain+0x2c/0x40 [Wed Nov 15 14:01:07 2023] [c00000000e233d50] [c0000000000cec44] opal_message_notify+0xf4/0x2a0 [Wed Nov 15 14:01:07 2023] [c00000000e233de0] [c000000000206d58] __handle_irq_event_percpu+0x78/0x240 [Wed Nov 15 14:01:07 2023] [c00000000e233e70] [c000000000207034] handle_irq_event+0x74/0x140 [Wed Nov 15 14:01:07 2023] [c00000000e233ea0] [c00000000020e9bc] handle_level_irq+0xdc/0x270 [Wed Nov 15 14:01:07 2023] [c00000000e233ed0] [c000000000204fb8] generic_handle_domain_irq+0x48/0x70 [Wed Nov 15 14:01:07 2023] [c00000000e233ef0] [c0000000000d6f38] opal_handle_events+0xb8/0x140 [Wed Nov 15 14:01:07 2023] [c00000000e233f50] [c0000000000ce514] kopald+0x84/0x110 [Wed Nov 15 14:01:07 2023] [c00000000e233f90] [c000000000190218] kthread+0x138/0x140 [Wed Nov 15 14:01:07 2023] [c00000000e233fe0] [c00000000000ded8] start_kernel_thread+0x14/0x18 [Wed Nov 15 14:01:07 2023] Code: 2c0a0000 4082ff48 3ca20000 e8a58050 3c620000 e8638058 39400001 38c00004 7fa4eb78 99490000 480004c5 e8410018 <0fe00000> 4bffff18 3860fff4 4bffff8c
[Wed Nov 15 14:01:07 2023] ---[ end trace 0000000000000000 ]---

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