6.6-stable review patch. If anyone has any objections, please let me know.
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From: Josephine Pfeiffer hi@josie.lol
[ Upstream commit a74f038fa50e0d33b740f44f862fe856f16de6a8 ]
The pt_dump_seq_puts() macro incorrectly uses seq_printf() instead of seq_puts(). This is both a performance issue and conceptually wrong, as the macro name suggests plain string output (puts) but the implementation uses formatted output (printf).
The macro is used in ptdump.c:301 to output a newline character. Using seq_printf() adds unnecessary overhead for format string parsing when outputting this constant string.
This bug was introduced in commit 59c4da8640cc ("riscv: Add support to dump the kernel page tables") in 2020, which copied the implementation pattern from other architectures that had the same bug.
Fixes: 59c4da8640cc ("riscv: Add support to dump the kernel page tables") Signed-off-by: Josephine Pfeiffer hi@josie.lol Link: https://lore.kernel.org/r/20251018170451.3355496-1-hi@josie.lol Signed-off-by: Paul Walmsley pjw@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/riscv/mm/ptdump.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c index e9090b38f8117..52cc3d9380c08 100644 --- a/arch/riscv/mm/ptdump.c +++ b/arch/riscv/mm/ptdump.c @@ -22,7 +22,7 @@ #define pt_dump_seq_puts(m, fmt) \ ({ \ if (m) \ - seq_printf(m, fmt); \ + seq_puts(m, fmt); \ })
/*