From: Yongxin Liu yongxin.liu@windriver.com

Zero can be a valid value of num_records. For example, on Intel Atom x6425RE, only x87 and SSE are supported (features 0, 1), and fpu_user_cfg.max_features is 3. The for_each_extended_xfeature() loop only iterates feature 2, which is not enabled, so num_records = 0. This is valid and should not cause core dump failure.

The issue is that dump_xsave_layout_desc() returns 0 for both genuine errors (dump_emit() failure) and valid cases (no extended features). Use negative return values for errors and only abort on genuine failures.

Cc: stable@vger.kernel.org Fixes: ba386777a30b ("x86/elf: Add a new FPU buffer layout info to x86 core files") Signed-off-by: Yongxin Liu yongxin.liu@windriver.com --- V2: Keep error checking but use negative value for genuine error V1: Remove error checking entirely --- arch/x86/kernel/fpu/xstate.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 48113c5193aa..76153dfb58c9 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1946,7 +1946,7 @@ static int dump_xsave_layout_desc(struct coredump_params *cprm) };

if (!dump_emit(cprm, &xc, sizeof(xc))) - return 0; + return -1;

num_records++; } @@ -1984,7 +1984,7 @@ int elf_coredump_extra_notes_write(struct coredump_params *cprm) return 1;

num_records = dump_xsave_layout_desc(cprm); - if (!num_records) + if (num_records < 0) return 1;

/* Total size should be equal to the number of records */