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Aleksei Nikiforov 13dcd6308c s390/fpu: Fix false-positive kmsan report in fpu_vstl() ... [ Upstream commit 14e4e4175b ] A false-positive kmsan report is detected when running ping command. An inline assembly instruction 'vstl' can write varied amount of bytes depending on value of 'index' argument. If 'index' > 0, 'vstl' writes at least 2 bytes. clang generates kmsan write helper call depending on inline assembly constraints. Constraints are evaluated compile-time, but value of 'index' argument is known only at runtime. clang currently generates call to __msan_instrument_asm_store with 1 byte as size. Manually call kmsan function to indicate correct amount of bytes written and fix false-positive report. This change fixes following kmsan reports: [ 36.563119] ===================================================== [ 36.563594] BUG: KMSAN: uninit-value in virtqueue_add+0x35c6/0x7c70 [ 36.563852] virtqueue_add+0x35c6/0x7c70 [ 36.564016] virtqueue_add_outbuf+0xa0/0xb0 [ 36.564266] start_xmit+0x288c/0x4a20 [ 36.564460] dev_hard_start_xmit+0x302/0x900 [ 36.564649] sch_direct_xmit+0x340/0xea0 [ 36.564894] __dev_queue_xmit+0x2e94/0x59b0 [ 36.565058] neigh_resolve_output+0x936/0xb40 [ 36.565278] __neigh_update+0x2f66/0x3a60 [ 36.565499] neigh_update+0x52/0x60 [ 36.565683] arp_process+0x1588/0x2de0 [ 36.565916] NF_HOOK+0x1da/0x240 [ 36.566087] arp_rcv+0x3e4/0x6e0 [ 36.566306] __netif_receive_skb_list_core+0x1374/0x15a0 [ 36.566527] netif_receive_skb_list_internal+0x1116/0x17d0 [ 36.566710] napi_complete_done+0x376/0x740 [ 36.566918] virtnet_poll+0x1bae/0x2910 [ 36.567130] __napi_poll+0xf4/0x830 [ 36.567294] net_rx_action+0x97c/0x1ed0 [ 36.567556] handle_softirqs+0x306/0xe10 [ 36.567731] irq_exit_rcu+0x14c/0x2e0 [ 36.567910] do_io_irq+0xd4/0x120 [ 36.568139] io_int_handler+0xc2/0xe8 [ 36.568299] arch_cpu_idle+0xb0/0xc0 [ 36.568540] arch_cpu_idle+0x76/0xc0 [ 36.568726] default_idle_call+0x40/0x70 [ 36.568953] do_idle+0x1d6/0x390 [ 36.569486] cpu_startup_entry+0x9a/0xb0 [ 36.569745] rest_init+0x1ea/0x290 [ 36.570029] start_kernel+0x95e/0xb90 [ 36.570348] startup_continue+0x2e/0x40 [ 36.570703] [ 36.570798] Uninit was created at: [ 36.571002] kmem_cache_alloc_node_noprof+0x9e8/0x10e0 [ 36.571261] kmalloc_reserve+0x12a/0x470 [ 36.571553] __alloc_skb+0x310/0x860 [ 36.571844] __ip_append_data+0x483e/0x6a30 [ 36.572170] ip_append_data+0x11c/0x1e0 [ 36.572477] raw_sendmsg+0x1c8c/0x2180 [ 36.572818] inet_sendmsg+0xe6/0x190 [ 36.573142] __sys_sendto+0x55e/0x8e0 [ 36.573392] __s390x_sys_socketcall+0x19ae/0x2ba0 [ 36.573571] __do_syscall+0x12e/0x240 [ 36.573823] system_call+0x6e/0x90 [ 36.573976] [ 36.574017] Byte 35 of 98 is uninitialized [ 36.574082] Memory access of size 98 starts at 0000000007aa0012 [ 36.574218] [ 36.574325] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G B N 6.17.0-dirty #16 NONE [ 36.574541] Tainted: [B]=BAD_PAGE, [N]=TEST [ 36.574617] Hardware name: IBM 3931 A01 703 (KVM/Linux) [ 36.574755] ===================================================== [ 63.532541] ===================================================== [ 63.533639] BUG: KMSAN: uninit-value in virtqueue_add+0x35c6/0x7c70 [ 63.533989] virtqueue_add+0x35c6/0x7c70 [ 63.534940] virtqueue_add_outbuf+0xa0/0xb0 [ 63.535861] start_xmit+0x288c/0x4a20 [ 63.536708] dev_hard_start_xmit+0x302/0x900 [ 63.537020] sch_direct_xmit+0x340/0xea0 [ 63.537997] __dev_queue_xmit+0x2e94/0x59b0 [ 63.538819] neigh_resolve_output+0x936/0xb40 [ 63.539793] ip_finish_output2+0x1ee2/0x2200 [ 63.540784] __ip_finish_output+0x272/0x7a0 [ 63.541765] ip_finish_output+0x4e/0x5e0 [ 63.542791] ip_output+0x166/0x410 [ 63.543771] ip_push_pending_frames+0x1a2/0x470 [ 63.544753] raw_sendmsg+0x1f06/0x2180 [ 63.545033] inet_sendmsg+0xe6/0x190 [ 63.546006] __sys_sendto+0x55e/0x8e0 [ 63.546859] __s390x_sys_socketcall+0x19ae/0x2ba0 [ 63.547730] __do_syscall+0x12e/0x240 [ 63.548019] system_call+0x6e/0x90 [ 63.548989] [ 63.549779] Uninit was created at: [ 63.550691] kmem_cache_alloc_node_noprof+0x9e8/0x10e0 [ 63.550975] kmalloc_reserve+0x12a/0x470 [ 63.551969] __alloc_skb+0x310/0x860 [ 63.552949] __ip_append_data+0x483e/0x6a30 [ 63.553902] ip_append_data+0x11c/0x1e0 [ 63.554912] raw_sendmsg+0x1c8c/0x2180 [ 63.556719] inet_sendmsg+0xe6/0x190 [ 63.557534] __sys_sendto+0x55e/0x8e0 [ 63.557875] __s390x_sys_socketcall+0x19ae/0x2ba0 [ 63.558869] __do_syscall+0x12e/0x240 [ 63.559832] system_call+0x6e/0x90 [ 63.560780] [ 63.560972] Byte 35 of 98 is uninitialized [ 63.561741] Memory access of size 98 starts at 0000000005704312 [ 63.561950] [ 63.562824] CPU: 3 UID: 0 PID: 192 Comm: ping Tainted: G B N 6.17.0-dirty #16 NONE [ 63.563868] Tainted: [B]=BAD_PAGE, [N]=TEST [ 63.564751] Hardware name: IBM 3931 A01 703 (KVM/Linux) [ 63.564986] ===================================================== Fixes: dcd3e1de9d ("s390/checksum: provide csum_partial_copy_nocheck()") Signed-off-by: Aleksei Nikiforov <aleksei.nikiforov@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		History 2025-12-18 14:03:00 +01:00
..
appldata	s390: Explicitly include <linux/export.h>	2025-06-17 18:18:02 +02:00
boot	s390 updates for 6.18 merge window	2025-09-29 19:14:25 -07:00
configs	s390: Update defconfigs	2025-10-24 15:25:43 +02:00
crypto	crypto: s390/phmac - Do not modify the req->nbytes value	2025-10-23 12:53:23 +08:00
hypfs	more s390 updates for 6.18 merge window	2025-10-09 10:51:43 -07:00
include	s390/fpu: Fix false-positive kmsan report in fpu_vstl()	2025-12-18 14:03:00 +01:00
kernel	s390/smp: Fix fallback CPU detection	2025-12-18 14:02:36 +01:00
kvm	more s390 updates for 6.18 merge window	2025-10-09 10:51:43 -07:00
lib	s390: Remove superfluous newlines from inline assemblies	2025-09-29 13:52:08 +02:00
mm	s390/mm: Fix __ptep_rdp() inline assembly	2025-11-14 15:58:20 +01:00
net	bpf, x86: Add support for signed arena loads	2025-09-23 12:00:22 -07:00
pci	s390/pci: Restore IRQ unconditionally for the zPCI device	2025-10-24 15:25:43 +02:00
purgatory	lib/crypto: sha256: Make library API use strongly-typed contexts	2025-07-04 10:18:53 -07:00
tools	s390: Allow to compile with z17 optimizations	2025-04-09 12:12:41 +02:00
Kbuild	- An extensive rework of kexec and crash Kconfig from Eric DeVolder	2023-08-29 14:53:51 -07:00
Kconfig	s390: Disable ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	2025-10-30 16:59:28 +01:00
Kconfig.debug	s390/mm: Add configurable STRICT_MM_TYPECHECKS	2025-03-11 15:27:34 +01:00
Makefile	s390: Add -Wno-pointer-sign to KBUILD_CFLAGS_DECOMPRESSOR	2025-09-29 13:52:08 +02:00
Makefile.postlink	kbuild: Create intermediate vmlinux build with relocations preserved	2025-03-17 00:29:50 +09:00