| Message ID | 20240617162708.492159-1-d.dulov@aladdin.ru (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | xdp: remove WARN() from __xdp_reg_mem_model() | expand |
On 17/06/2024 18.27, Daniil Dulov wrote: > 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> > --- > net/core/xdp.c | 1 - > 1 file changed, 1 deletion(-) > Sure, looks like we can remove this WARN_ON() Acked-by: Jesper Dangaard Brouer <hawk@kernel.org> > diff --git a/net/core/xdp.c b/net/core/xdp.c > index 41693154e426..fb2f00e3f701 100644 > --- a/net/core/xdp.c > +++ b/net/core/xdp.c > @@ -296,7 +296,6 @@ static struct xdp_mem_allocator *__xdp_reg_mem_model(struct xdp_mem_info *mem, > ret = __mem_id_init_hash_table(); > mutex_unlock(&mem_id_lock); > if (ret < 0) { > - WARN_ON(1); > return ERR_PTR(ret); > } > }
On Mon, 17 Jun 2024 19:27:08 +0300 Daniil Dulov wrote: > if (ret < 0) { > - WARN_ON(1); > return ERR_PTR(ret); > } nit: the brackets are no longer necessary, then
diff --git a/net/core/xdp.c b/net/core/xdp.c index 41693154e426..fb2f00e3f701 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -296,7 +296,6 @@ static struct xdp_mem_allocator *__xdp_reg_mem_model(struct xdp_mem_info *mem, ret = __mem_id_init_hash_table(); mutex_unlock(&mem_id_lock); if (ret < 0) { - WARN_ON(1); return ERR_PTR(ret); } }
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> --- net/core/xdp.c | 1 - 1 file changed, 1 deletion(-)