git/linux-net
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/ synced 2026-04-18 06:33:43 -04:00
Code Issues Packages Projects Releases Wiki Activity

selftests/bpf: Fix tests after fields reorder in struct file

Browse Source 
The change in struct file [1] moved f_ref to the 3rd cache line.
It made *(u64 *)file dereference invalid from the verifier point of view,
because btf_struct_walk() walks into f_lock field, which is 4-byte long.

Fix the selftests to deference the file pointer as a 4-byte access.

[1] commit e249056c91 ("fs: place f_ref to 3rd cache line in struct file to resolve false sharing")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20250327185528.1740787-1-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Song Liu
2025-03-27 11:55:28 -07:00
committed by Alexei Starovoitov
parent 5d0b204654
commit 00387808d3
2 changed files with 4 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
tools/testing/selftests/bpf/progs/test_module_attach.c
View File

@@ -117,7 +117,7 @@ int BPF_PROG(handle_fexit_ret, int arg, struct file *ret)
bpf_probe_read_kernel(&buf, 8, ret);
bpf_probe_read_kernel(&buf, 8, (char *)ret + 256);
*(volatile long long *)ret;
*(volatile int *)ret;
*(volatile int *)&ret->f_mode;
return 0;
}