On Sat, 2020-12-12 at 22:05 -0800, akpm@xxxxxxxxxxxxxxxxxxxx wrote: > The patch titled > Subject: kasan: fix object remaining in offline per-cpu quarantine > has been removed from the -mm tree. Its filename was > kasan-fix-object-remain-in-offline-per-cpu-quarantine.patch > > This patch was dropped because it was merged into mainline or a subsystem tree > Hi Andrew, Sorry to bother. This patch has dependency with two patches of Andrey's patch series as below. "kasan: rename get_alloc/free_info" "kasan: sanitize objects when metadata doesnt fit" If only merge this patch, it may cause some memory leak. Could you please merge Andrey's whole patch series in mm-tree into mainline together? Thanks. > ------------------------------------------------------ > From: Kuan-Ying Lee <Kuan-Ying.Lee@xxxxxxxxxxxx> > Subject: kasan: fix object remaining in offline per-cpu quarantine > > We hit this issue in our internal test. When enabling generic kasan, a > kfree()'d object is put into per-cpu quarantine first. If the cpu goes > offline, object still remains in the per-cpu quarantine. If we call > kmem_cache_destroy() now, slub will report "Objects remaining" error. > > [ 74.982625] ============================================================================= > [ 74.983380] BUG test_module_slab (Not tainted): Objects remaining in test_module_slab on __kmem_cache_shutdown() > [ 74.984145] ----------------------------------------------------------------------------- > [ 74.984145] > [ 74.984883] Disabling lock debugging due to kernel taint > [ 74.985561] INFO: Slab 0x(____ptrval____) objects=34 used=1 fp=0x(____ptrval____) flags=0x2ffff00000010200 > [ 74.986638] CPU: 3 PID: 176 Comm: cat Tainted: G B 5.10.0-rc1-00007-g4525c8781ec0-dirty #10 > [ 74.987262] Hardware name: linux,dummy-virt (DT) > [ 74.987606] Call trace: > [ 74.987924] dump_backtrace+0x0/0x2b0 > [ 74.988296] show_stack+0x18/0x68 > [ 74.988698] dump_stack+0xfc/0x168 > [ 74.989030] slab_err+0xac/0xd4 > [ 74.989346] __kmem_cache_shutdown+0x1e4/0x3c8 > [ 74.989779] kmem_cache_destroy+0x68/0x130 > [ 74.990176] test_version_show+0x84/0xf0 > [ 74.990679] module_attr_show+0x40/0x60 > [ 74.991218] sysfs_kf_seq_show+0x128/0x1c0 > [ 74.991656] kernfs_seq_show+0xa0/0xb8 > [ 74.992059] seq_read+0x1f0/0x7e8 > [ 74.992415] kernfs_fop_read+0x70/0x338 > [ 74.993051] vfs_read+0xe4/0x250 > [ 74.993498] ksys_read+0xc8/0x180 > [ 74.993825] __arm64_sys_read+0x44/0x58 > [ 74.994203] el0_svc_common.constprop.0+0xac/0x228 > [ 74.994708] do_el0_svc+0x38/0xa0 > [ 74.995088] el0_sync_handler+0x170/0x178 > [ 74.995497] el0_sync+0x174/0x180 > [ 74.996050] INFO: Object 0x(____ptrval____) @offset=15848 > [ 74.996752] INFO: Allocated in test_version_show+0x98/0xf0 age=8188 cpu=6 pid=172 > [ 75.000802] stack_trace_save+0x9c/0xd0 > [ 75.002420] set_track+0x64/0xf0 > [ 75.002770] alloc_debug_processing+0x104/0x1a0 > [ 75.003171] ___slab_alloc+0x628/0x648 > [ 75.004213] __slab_alloc.isra.0+0x2c/0x58 > [ 75.004757] kmem_cache_alloc+0x560/0x588 > [ 75.005376] test_version_show+0x98/0xf0 > [ 75.005756] module_attr_show+0x40/0x60 > [ 75.007035] sysfs_kf_seq_show+0x128/0x1c0 > [ 75.007433] kernfs_seq_show+0xa0/0xb8 > [ 75.007800] seq_read+0x1f0/0x7e8 > [ 75.008128] kernfs_fop_read+0x70/0x338 > [ 75.008507] vfs_read+0xe4/0x250 > [ 75.008990] ksys_read+0xc8/0x180 > [ 75.009462] __arm64_sys_read+0x44/0x58 > [ 75.010085] el0_svc_common.constprop.0+0xac/0x228 > [ 75.011006] kmem_cache_destroy test_module_slab: Slab cache still has objects > > Register a cpu hotplug function to remove all objects in the offline > per-cpu quarantine when cpu is going offline. Set a per-cpu variable to > indicate this cpu is offline. > > [qiang.zhang@xxxxxxxxxxxxx: fix slab double free when cpu-hotplug] > Link: https://lkml.kernel.org/r/20201204102206.20237-1-qiang.zhang@xxxxxxxxxxxxx > Link: https://lkml.kernel.org/r/1606895585-17382-2-git-send-email-Kuan-Ying.Lee@xxxxxxxxxxxx > Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@xxxxxxxxxxxx> > Signed-off-by: Zqiang <qiang.zhang@xxxxxxxxxxxxx> > Suggested-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > Reported-by: Guangye Yang <guangye.yang@xxxxxxxxxxxx> > Reviewed-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> > Cc: Alexander Potapenko <glider@xxxxxxxxxx> > Cc: Matthias Brugger <matthias.bgg@xxxxxxxxx> > Cc: Nicholas Tang <nicholas.tang@xxxxxxxxxxxx> > Cc: Miles Chen <miles.chen@xxxxxxxxxxxx> > Cc: Qian Cai <qcai@xxxxxxxxxx> > Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > --- > > mm/kasan/quarantine.c | 39 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > > --- a/mm/kasan/quarantine.c~kasan-fix-object-remain-in-offline-per-cpu-quarantine > +++ a/mm/kasan/quarantine.c > @@ -29,6 +29,7 @@ > #include <linux/srcu.h> > #include <linux/string.h> > #include <linux/types.h> > +#include <linux/cpuhotplug.h> > > #include "../slab.h" > #include "kasan.h" > @@ -43,6 +44,7 @@ struct qlist_head { > struct qlist_node *head; > struct qlist_node *tail; > size_t bytes; > + bool offline; > }; > > #define QLIST_INIT { NULL, NULL, 0 } > @@ -188,6 +190,10 @@ void quarantine_put(struct kasan_free_me > local_irq_save(flags); > > q = this_cpu_ptr(&cpu_quarantine); > + if (q->offline) { > + local_irq_restore(flags); > + return; > + } > qlist_put(q, &info->quarantine_link, cache->size); > if (unlikely(q->bytes > QUARANTINE_PERCPU_SIZE)) { > qlist_move_all(q, &temp); > @@ -328,3 +334,36 @@ void quarantine_remove_cache(struct kmem > > synchronize_srcu(&remove_cache_srcu); > } > + > +static int kasan_cpu_online(unsigned int cpu) > +{ > + this_cpu_ptr(&cpu_quarantine)->offline = false; > + return 0; > +} > + > +static int kasan_cpu_offline(unsigned int cpu) > +{ > + struct qlist_head *q; > + > + q = this_cpu_ptr(&cpu_quarantine); > + /* Ensure the ordering between the writing to q->offline and > + * qlist_free_all. Otherwise, cpu_quarantine may be corrupted > + * by interrupt. > + */ > + WRITE_ONCE(q->offline, true); > + barrier(); > + qlist_free_all(q, NULL); > + return 0; > +} > + > +static int __init kasan_cpu_quarantine_init(void) > +{ > + int ret = 0; > + > + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "mm/kasan:online", > + kasan_cpu_online, kasan_cpu_offline); > + if (ret < 0) > + pr_err("kasan cpu quarantine register failed [%d]\n", ret); > + return ret; > +} > +late_initcall(kasan_cpu_quarantine_init); > _ > > Patches currently in -mm which might be from Kuan-Ying.Lee@xxxxxxxxxxxx are > >
