Syzkaller reports a warning in __xdp_reg_mem_model().
The warning occurs only if __mem_id_init_hash_table() returns
an error. It returns the error in two cases:
1. memory allocation fails;
2. rhashtable_init() fails when some fields of rhashtable_params
struct are not initialized properly.
The second case cannot happen since there is a static const
rhashtable_params struct with valid fields. So, warning is only triggered
when there is a problem with memory allocation.
Thus, there is no sense in using WARN() to handle this error and it can be
safely removed.
WARNING: CPU: 0 PID: 5065 at net/core/xdp.c:299 __xdp_reg_mem_model+0x2d9/0x650 net/core/xdp.c:299
CPU: 0 PID: 5065 Comm: syz-executor883 Not tainted 6.8.0-syzkaller-05271-gf99c5f563c17 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:__xdp_reg_mem_model+0x2d9/0x650 net/core/xdp.c:299
Call Trace:
xdp_reg_mem_model+0x22/0x40 net/core/xdp.c:344
xdp_test_run_setup net/bpf/test_run.c:188 [inline]
bpf_test_run_xdp_live+0x365/0x1e90 net/bpf/test_run.c:377
bpf_prog_test_run_xdp+0x813/0x11b0 net/bpf/test_run.c:1267
bpf_prog_test_run+0x33a/0x3b0 kernel/bpf/syscall.c:4240
__sys_bpf+0x48d/0x810 kernel/bpf/syscall.c:5649
__do_sys_bpf kernel/bpf/syscall.c:5738 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5736 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5736
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: 8d5d88527587 ("xdp: rhashtable with allocator ID to pointer mapping")
Signed-off-by: Daniil Dulov <d.dulov@xxxxxxxxxx>
Acked-by: Jesper Dangaard Brouer <hawk@xxxxxxxxxx>
---
v2: Removed unnecessary brackets as Jakub Kicinski <kuba@xxxxxxxxxx>
suggested, also added Acked-by Jesper Dangaard Brouer <hawk@xxxxxxxxxx>
Link: https://lore.kernel.org/all/20240617162708.492159-1-d.dulov@xxxxxxxxxx/
net/core/xdp.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 41693154e426..022c12059cf2 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -295,10 +295,8 @@ static struct xdp_mem_allocator *__xdp_reg_mem_model(struct xdp_mem_info *mem,
mutex_lock(&mem_id_lock);
ret = __mem_id_init_hash_table();
mutex_unlock(&mem_id_lock);
- if (ret < 0) {
- WARN_ON(1);
+ if (ret < 0)
return ERR_PTR(ret);
- }
}
xdp_alloc = kzalloc(sizeof(*xdp_alloc), gfp);
--
2.25.1
