change the allocator flag of idr_alloc_u32 from GFP_ATOMIC to GFP_KERNEL, as GFP_ATOMIC caused BUG: "using smp_processor_id() in preemptible" as reported by syzkaller.
Reported-by: syzbot+3eec59e770685e3dc...@syzkaller.appspotmail.com Signed-off-by: Du Cheng <duche...@gmail.com> --- Hi David & Jakub, Although this is a simple fix to make syzkaller happy, I feel that maybe a more proper fix is to convert qrtr_ports from using IDR to radix_tree (which is in fact xarray) ? I found some previous work done in 2019 by Matthew Wilcox: https://lore.kernel.org/netdev/20190820223259.22348-1-wi...@infradead.org/t/#mcb60ad4c34e35a6183c7353c8a44ceedfcff297d but that was not merged as of now. My wild guess is that it was probably in conflicti with the conversion of radix_tree to xarray during 2020, and that might cause the direct use of xarray in qrtr.c unfavorable. Shall I proceed with converting qrtr_pors to use radix_tree (or just xarray)? Regards, Du Cheng net/qrtr/qrtr.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c index edb6ac17ceca..ee42e1e1d4d4 100644 --- a/net/qrtr/qrtr.c +++ b/net/qrtr/qrtr.c @@ -722,17 +722,17 @@ static int qrtr_port_assign(struct qrtr_sock *ipc, int *port) mutex_lock(&qrtr_port_lock); if (!*port) { min_port = QRTR_MIN_EPH_SOCKET; - rc = idr_alloc_u32(&qrtr_ports, ipc, &min_port, QRTR_MAX_EPH_SOCKET, GFP_ATOMIC); + rc = idr_alloc_u32(&qrtr_ports, ipc, &min_port, QRTR_MAX_EPH_SOCKET, GFP_KERNEL); if (!rc) *port = min_port; } else if (*port < QRTR_MIN_EPH_SOCKET && !capable(CAP_NET_ADMIN)) { rc = -EACCES; } else if (*port == QRTR_PORT_CTRL) { min_port = 0; - rc = idr_alloc_u32(&qrtr_ports, ipc, &min_port, 0, GFP_ATOMIC); + rc = idr_alloc_u32(&qrtr_ports, ipc, &min_port, 0, GFP_KERNEL); } else { min_port = *port; - rc = idr_alloc_u32(&qrtr_ports, ipc, &min_port, *port, GFP_ATOMIC); + rc = idr_alloc_u32(&qrtr_ports, ipc, &min_port, *port, GFP_KERNEL); if (!rc) *port = min_port; } -- 2.27.0
