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Commit 5c76e8de authored by Sergey Matyukevich's avatar Sergey Matyukevich Committed by Phil Elwell
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riscv: prevent pt_regs corruption for secondary idle threads



commit a638b046 upstream.

Top of the kernel thread stack should be reserved for pt_regs. However
this is not the case for the idle threads of the secondary boot harts.
Their stacks overlap with their pt_regs, so both may get corrupted.

Similar issue has been fixed for the primary hart, see c7cdd96e
("riscv: prevent stack corruption by reserving task_pt_regs(p) early").
However that fix was not propagated to the secondary harts. The problem
has been noticed in some CPU hotplug tests with V enabled. The function
smp_callin stored several registers on stack, corrupting top of pt_regs
structure including status field. As a result, kernel attempted to save
or restore inexistent V context.

Fixes: 9a2451f1 ("RISC-V: Avoid using per cpu array for ordered booting")
Fixes: 2875fe05 ("RISC-V: Add cpu_ops and modify default booting method")
Signed-off-by: default avatarSergey Matyukevich <sergey.matyukevich@syntacore.com>
Reviewed-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20240523084327.2013211-1-geomatsi@gmail.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8aad5ca9
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