On Mon, Apr 01, 2019 at 02:45:54PM -0300, Jason Gunthorpe wrote: > On Mon, Apr 01, 2019 at 10:36:05AM -0700, syzbot wrote: > > Hello, > > > > syzbot found the following crash on: > > > > HEAD commit: e3ecb83e Add linux-next specific files for 20190401 > > git tree: linux-next > > console output: https://syzkaller.appspot.com/x/log.txt?x=13bc36cd200000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=db6c9f2bfeb91a99 > > dashboard link: https://syzkaller.appspot.com/bug?extid=2e3e485d5697ea610460 > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > > Unfortunately, I don't have any reproducer for this crash yet. > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+2e3e485d5697ea610460@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > WARNING: CPU: 1 PID: 7 at drivers/infiniband/core/cma.c:4674 > > cma_exit_net+0x327/0x390 drivers/infiniband/core/cma.c:4674 > > Kernel panic - not syncing: panic_on_warn set ... > > Matt: This is why the WARN_ON(!xa_empty()) is so valuable. Magically > syzkaller can find something in this code is buggy. > > Mellanox is also showing a different testing failure over the weekend > (use after free or something) from your 'cma: Convert portspace IDRs > to XArray' This is what I see in my environment. [ 72.725596] ================================================================== [ 72.726017] BUG: KASAN: use-after-free in cma_check_port+0x86a/0xa20 [rdma_cm] [ 72.726263] Read of size 8 at addr ffff888069fde998 by task ucmatose/387 [ 72.726460] [ 72.726550] CPU: 3 PID: 387 Comm: ucmatose Not tainted 5.1.0-rc2+ #253 [ 72.726751] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org 04/01/2014 [ 72.727119] Call Trace: [ 72.727210] dump_stack+0x7c/0xc0 [ 72.727342] print_address_description+0x6c/0x23c [ 72.727505] ? cma_check_port+0x86a/0xa20 [rdma_cm] [ 72.727666] kasan_report.cold.3+0x1c/0x35 [ 72.727805] ? cma_check_port+0x86a/0xa20 [rdma_cm] [ 72.727977] ? cma_check_port+0x86a/0xa20 [rdma_cm] [ 72.728138] cma_check_port+0x86a/0xa20 [rdma_cm] [ 72.728306] rdma_bind_addr+0x11bc/0x1b00 [rdma_cm] [ 72.728465] ? find_held_lock+0x33/0x1c0 [ 72.728597] ? cma_ndev_work_handler+0x180/0x180 [rdma_cm] [ 72.728756] ? wait_for_completion+0x3d0/0x3d0 [ 72.728928] ucma_bind+0x120/0x160 [rdma_ucm] [ 72.729089] ? ucma_resolve_addr+0x1a0/0x1a0 [rdma_ucm] [ 72.729256] ucma_write+0x1f8/0x2b0 [rdma_ucm] [ 72.729409] ? ucma_open+0x260/0x260 [rdma_ucm] [ 72.729571] vfs_write+0x157/0x460 [ 72.729688] ksys_write+0xb8/0x170 [ 72.729828] ? __ia32_sys_read+0xb0/0xb0 [ 72.729954] ? trace_hardirqs_off_caller+0x5b/0x160 [ 72.730107] ? do_syscall_64+0x18/0x3c0 [ 72.730243] do_syscall_64+0x95/0x3c0 [ 72.730363] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 72.730508] RIP: 0033:0x7f6f1758fff8 [ 72.730624] Code: 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 25 77 0d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 49 89 d4 55 [ 72.731146] RSP: 002b:00007fff99f99088 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 72.731365] RAX: ffffffffffffffda RBX: 00007fff99f99090 RCX: 00007f6f1758fff8 [ 72.731579] RDX: 0000000000000090 RSI: 00007fff99f99090 RDI: 0000000000000003 [ 72.731814] RBP: 0000564942bd8ec0 R08: 0000564942bd9180 R09: 0000000000000000 [ 72.732043] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 72.732262] R13: 0000000000000001 R14: 0000000000000000 R15: 00005649413cc470 [ 72.732494] [ 72.732572] Allocated by task 381: [ 72.732692] __kasan_kmalloc.constprop.5+0xc1/0xd0 [ 72.732857] cma_alloc_port+0x4d/0x160 [rdma_cm] [ 72.733006] rdma_bind_addr+0x14e7/0x1b00 [rdma_cm] [ 72.733153] ucma_bind+0x120/0x160 [rdma_ucm] [ 72.733299] ucma_write+0x1f8/0x2b0 [rdma_ucm] [ 72.733452] vfs_write+0x157/0x460 [ 72.733569] ksys_write+0xb8/0x170 [ 72.733675] do_syscall_64+0x95/0x3c0 [ 72.733800] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 72.733956] [ 72.734029] Freed by task 381: [ 72.734133] __kasan_slab_free+0x12e/0x180 [ 72.734284] kfree+0xed/0x290 [ 72.734399] rdma_destroy_id+0x6b6/0x9e0 [rdma_cm] [ 72.734559] ucma_close+0x110/0x300 [rdma_ucm] [ 72.734701] __fput+0x25a/0x740 [ 72.734832] task_work_run+0x10e/0x190 [ 72.734959] do_exit+0x85e/0x29e0 [ 72.735071] do_group_exit+0xf0/0x2e0 [ 72.735182] get_signal+0x2e0/0x17e0 [ 72.735304] do_signal+0x94/0x1570 [ 72.735424] exit_to_usermode_loop+0xfa/0x130 [ 72.735612] do_syscall_64+0x327/0x3c0 [ 72.735756] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 72.735941] [ 72.736033] The buggy address belongs to the object at ffff888069fde990 [ 72.736033] which belongs to the cache kmalloc-32 of size 32 [ 72.736414] The buggy address is located 8 bytes inside of [ 72.736414] 32-byte region [ffff888069fde990, ffff888069fde9b0) [ 72.736777] The buggy address belongs to the page: [ 72.736940] page:ffffea0001a7f780 count:1 mapcount:0 mapping:ffff88806bc03980 index:0x0 [ 72.737171] flags: 0x4000000000000200(slab) [ 72.737295] raw: 4000000000000200 dead000000000100 dead000000000200 ffff88806bc03980 [ 72.737525] raw: 0000000000000000 0000000000550055 00000001ffffffff 0000000000000000 [ 72.737786] page dumped because: kasan: bad access detected [ 72.737948] [ 72.738019] Memory state around the buggy address: [ 72.738164] ffff888069fde880: fb fb fc fc fb fb fb fb fc fc fb fb fb fb fc fc [ 72.738396] ffff888069fde900: fb fb fb fb fc fc fb fb fb fb fc fc fb fb fb fb [ 72.738627] >ffff888069fde980: fc fc fb fb fb fb fc fc fb fb fb fb fc fc fb fb [ 72.738869] ^ [ 72.738999] ffff888069fdea00: fb fb fc fc fb fb fb fb fc fc fb fb fb fb fc fc [ 72.739213] ffff888069fdea80: fb fb fb fb fc fc fb fb fb fb fc fc fb fb fb fb [ 72.739431] ================================================================== [ 72.739667] Disabling lock debugging due to kernel taint > > If you seem something obvious wrong in that patch please speak > up.. Below is what I applied. > > Thanks, > Jason > > diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c > index 68c997be242930..a8b9c66c85252b 100644 > --- a/drivers/infiniband/core/cma.c > +++ b/drivers/infiniband/core/cma.c > @@ -39,7 +39,7 @@ > #include <linux/mutex.h> > #include <linux/random.h> > #include <linux/igmp.h> > -#include <linux/idr.h> > +#include <linux/xarray.h> > #include <linux/inetdevice.h> > #include <linux/slab.h> > #include <linux/module.h> > @@ -191,10 +191,10 @@ static struct workqueue_struct *cma_wq; > static unsigned int cma_pernet_id; > > struct cma_pernet { > - struct idr tcp_ps; > - struct idr udp_ps; > - struct idr ipoib_ps; > - struct idr ib_ps; > + struct xarray tcp_ps; > + struct xarray udp_ps; > + struct xarray ipoib_ps; > + struct xarray ib_ps; > }; > > static struct cma_pernet *cma_pernet(struct net *net) > @@ -202,7 +202,8 @@ static struct cma_pernet *cma_pernet(struct net *net) > return net_generic(net, cma_pernet_id); > } > > -static struct idr *cma_pernet_idr(struct net *net, enum rdma_ucm_port_space ps) > +static > +struct xarray *cma_pernet_xa(struct net *net, enum rdma_ucm_port_space ps) > { > struct cma_pernet *pernet = cma_pernet(net); > > @@ -247,25 +248,25 @@ struct class_port_info_context { > static int cma_ps_alloc(struct net *net, enum rdma_ucm_port_space ps, > struct rdma_bind_list *bind_list, int snum) > { > - struct idr *idr = cma_pernet_idr(net, ps); > + struct xarray *xa = cma_pernet_xa(net, ps); > > - return idr_alloc(idr, bind_list, snum, snum + 1, GFP_KERNEL); > + return xa_insert(xa, snum, bind_list, GFP_KERNEL); > } > > static struct rdma_bind_list *cma_ps_find(struct net *net, > enum rdma_ucm_port_space ps, int snum) > { > - struct idr *idr = cma_pernet_idr(net, ps); > + struct xarray *xa = cma_pernet_xa(net, ps); > > - return idr_find(idr, snum); > + return xa_load(xa, snum); > } > > static void cma_ps_remove(struct net *net, enum rdma_ucm_port_space ps, > int snum) > { > - struct idr *idr = cma_pernet_idr(net, ps); > + struct xarray *xa = cma_pernet_xa(net, ps); > > - idr_remove(idr, snum); > + xa_erase(xa, snum); > } > > enum { > @@ -4655,10 +4656,10 @@ static int cma_init_net(struct net *net) > { > struct cma_pernet *pernet = cma_pernet(net); > > - idr_init(&pernet->tcp_ps); > - idr_init(&pernet->udp_ps); > - idr_init(&pernet->ipoib_ps); > - idr_init(&pernet->ib_ps); > + xa_init(&pernet->tcp_ps); > + xa_init(&pernet->udp_ps); > + xa_init(&pernet->ipoib_ps); > + xa_init(&pernet->ib_ps); > > return 0; > } > @@ -4667,10 +4668,10 @@ static void cma_exit_net(struct net *net) > { > struct cma_pernet *pernet = cma_pernet(net); > > - idr_destroy(&pernet->tcp_ps); > - idr_destroy(&pernet->udp_ps); > - idr_destroy(&pernet->ipoib_ps); > - idr_destroy(&pernet->ib_ps); > + WARN_ON(!xa_empty(&pernet->tcp_ps)); > + WARN_ON(!xa_empty(&pernet->udp_ps)); > + WARN_ON(!xa_empty(&pernet->ipoib_ps)); > + WARN_ON(!xa_empty(&pernet->ib_ps)); > } > > static struct pernet_operations cma_pernet_operations = { >
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