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Filename	Latest commit message	Latest commit date
He Ying 348831a9e8 powerpc/kasan: Silence KASAN warnings in __get_wchan() ... [ Upstream commit a1b29ba2f2c171b9bea73be993bfdf0a62d37d15 ] The following KASAN warning was reported in our kernel. BUG: KASAN: stack-out-of-bounds in get_wchan+0x188/0x250 Read of size 4 at addr d216f958 by task ps/14437 CPU: 3 PID: 14437 Comm: ps Tainted: G O 5.10.0 #1 Call Trace: [daa63858] [c0654348] dump_stack+0x9c/0xe4 (unreliable) [daa63888] [c035cf0c] print_address_description.constprop.3+0x8c/0x570 [daa63908] [c035d6bc] kasan_report+0x1ac/0x218 [daa63948] [c00496e8] get_wchan+0x188/0x250 [daa63978] [c0461ec8] do_task_stat+0xce8/0xe60 [daa63b98] [c0455ac8] proc_single_show+0x98/0x170 [daa63bc8] [c03cab8c] seq_read_iter+0x1ec/0x900 [daa63c38] [c03cb47c] seq_read+0x1dc/0x290 [daa63d68] [c037fc94] vfs_read+0x164/0x510 [daa63ea8] [c03808e4] ksys_read+0x144/0x1d0 [daa63f38] [c005b1dc] ret_from_syscall+0x0/0x38 --- interrupt: c00 at 0x8fa8f4 LR = 0x8fa8cc The buggy address belongs to the page: page:98ebcdd2 refcount:0 mapcount:0 mapping:00000000 index:0x2 pfn:0x1216f flags: 0x0() raw: 00000000 00000000 01010122 00000000 00000002 00000000 ffffffff 00000000 raw: 00000000 page dumped because: kasan: bad access detected Memory state around the buggy address: d216f800: 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00 00 00 d216f880: f2 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >d216f900: 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 ^ d216f980: f2 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 00 00 d216fa00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 After looking into this issue, I find the buggy address belongs to the task stack region. It seems KASAN has something wrong. I look into the code of __get_wchan in x86 architecture and find the same issue has been resolved by the commit f7d27c35dd ("x86/mm, kasan: Silence KASAN warnings in get_wchan()"). The solution could be applied to powerpc architecture too. As Andrey Ryabinin said, get_wchan() is racy by design, it may access volatile stack of running task, thus it may access redzone in a stack frame and cause KASAN to warn about this. Use READ_ONCE_NOCHECK() to silence these warnings. Reported-by: Wanming Hu <huwanming@huaweil.com> Signed-off-by: He Ying <heying24@huawei.com> Signed-off-by: Chen Jingwen <chenjingwen6@huawei.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220121014418.155675-1-heying24@huawei.com Signed-off-by: Sasha Levin <sashal@kernel.org>		2022-06-22 14:11:19 +02:00
..
boot	powerpc: dts: t104xrdb: fix phy type for FMAN 4/5	2022-04-15 14:18:32 +02:00
configs	powerpc/config: Renable MTD_PHYSMAP_OF	2021-09-22 12:26:24 +02:00
crypto
include	powerpc: define get_cycles macro for arch-override	2022-06-22 14:11:15 +02:00
kernel	powerpc/kasan: Silence KASAN warnings in __get_wchan()	2022-06-22 14:11:19 +02:00
kvm	KVM: PPC: Fix TCE handling for VFIO	2022-04-27 13:50:49 +02:00
lib	powerpc/lib/sstep: Fix build errors with newer binutils	2022-04-15 14:18:25 +02:00
math-emu
mm	powerpc/kasan: Fix early region not updated correctly	2022-04-15 14:18:29 +02:00
net	powerpc/bpf: Emit stf barrier instruction sequences for BPF_NOSPEC	2021-11-17 09:48:49 +01:00
oprofile
perf	powerpc/perf: Fix the threshold compare group constraint for power9	2022-06-14 18:11:42 +02:00
platforms	powerpc/4xx/cpm: Fix return value of __setup() handler	2022-06-14 18:11:41 +02:00
purgatory
sysdev	powerpc/fsl_rio: Fix refcount leak in fsl_rio_setup	2022-06-14 18:11:42 +02:00
tools
xmon	powerpc/xmon: Change printk() to pr_cont()	2020-12-30 11:51:39 +01:00
Kbuild
Kconfig	powerpc: Fix HAVE_HARDLOCKUP_DETECTOR_ARCH build configuration	2021-05-14 09:44:26 +02:00
Kconfig.debug	powerpc: iommu: fix build when neither PCI or IBMVIO is set	2021-05-14 09:44:28 +02:00
Makefile	powerpc/Makefile: Don't pass -mcpu=powerpc64 when building 32-bit	2022-04-15 14:18:14 +02:00
Makefile.postlink