5.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Daniil Dulov d.dulov@aladdin.ru
[ Upstream commit 7e9f79428372c6eab92271390851be34ab26bfb4 ]
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@aladdin.ru Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Jesper Dangaard Brouer hawk@kernel.org Link: https://lore.kernel.org/all/20240617162708.492159-1-d.dulov@aladdin.ru Link: https://lore.kernel.org/bpf/20240624080747.36858-1-d.dulov@aladdin.ru Signed-off-by: Sasha Levin sashal@kernel.org --- 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 6e6b89d5f77ed..eb5045924efaa 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -291,10 +291,8 @@ 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);