khugepaged deadlock #17
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"commit 675d995 possible fix. |
liyi-ibm
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commit 360cc79 upstream. The table field in nft_obj_filter is not an array. In order to check tablename, we should check if the pointer is set. Test commands: %nft add table ip filter %nft add counter ip filter ct1 %nft reset counters Splat looks like: [ 306.510504] kasan: CONFIG_KASAN_INLINE enabled [ 306.516184] kasan: GPF could be caused by NULL-ptr deref or user memory access [ 306.524775] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI [ 306.528284] Modules linked in: nft_objref nft_counter nf_tables nfnetlink ip_tables x_tables [ 306.528284] CPU: 0 PID: 1488 Comm: nft Not tainted 4.17.0-rc4+ #17 [ 306.528284] Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 07/08/2015 [ 306.528284] RIP: 0010:nf_tables_dump_obj+0x52c/0xa70 [nf_tables] [ 306.528284] RSP: 0018:ffff8800b6cb7520 EFLAGS: 00010246 [ 306.528284] RAX: 0000000000000000 RBX: ffff8800b6c49820 RCX: 0000000000000000 [ 306.528284] RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffffed0016d96e9a [ 306.528284] RBP: ffff8800b6cb75c0 R08: ffffed00236fce7c R09: ffffed00236fce7b [ 306.528284] R10: ffffffff9f6241e8 R11: ffffed00236fce7c R12: ffff880111365108 [ 306.528284] R13: 0000000000000000 R14: ffff8800b6c49860 R15: ffff8800b6c49860 [ 306.528284] FS: 00007f838b007700(0000) GS:ffff88011b600000(0000) knlGS:0000000000000000 [ 306.528284] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 306.528284] CR2: 00007ffeafabcf78 CR3: 00000000b6cbe000 CR4: 00000000001006f0 [ 306.528284] Call Trace: [ 306.528284] netlink_dump+0x470/0xa20 [ 306.528284] __netlink_dump_start+0x5ae/0x690 [ 306.528284] ? nf_tables_getobj+0x1b3/0x740 [nf_tables] [ 306.528284] nf_tables_getobj+0x2f5/0x740 [nf_tables] [ 306.528284] ? nft_obj_notify+0x100/0x100 [nf_tables] [ 306.528284] ? nf_tables_getobj+0x740/0x740 [nf_tables] [ 306.528284] ? nf_tables_dump_flowtable_done+0x70/0x70 [nf_tables] [ 306.528284] ? nft_obj_notify+0x100/0x100 [nf_tables] [ 306.528284] nfnetlink_rcv_msg+0x8ff/0x932 [nfnetlink] [ 306.528284] ? nfnetlink_rcv_msg+0x216/0x932 [nfnetlink] [ 306.528284] netlink_rcv_skb+0x1c9/0x2f0 [ 306.528284] ? nfnetlink_bind+0x1d0/0x1d0 [nfnetlink] [ 306.528284] ? debug_check_no_locks_freed+0x270/0x270 [ 306.528284] ? netlink_ack+0x7a0/0x7a0 [ 306.528284] ? ns_capable_common+0x6e/0x110 [ ... ] Fixes: e46abbc ("netfilter: nf_tables: Allow table names of up to 255 chars") Signed-off-by: Taehee Yoo <ap420073@gmail.com> Acked-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
liyi-ibm
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Dec 28, 2018
commit 67d2f87 upstream. Commit dec2c92 ("Bluetooth: hci_ldisc: Use rwlocking to avoid closing proto races") introduced locks in hci_ldisc that are held while calling the proto functions. These locks are rwlock's, and hence do not allow sleeping while they are held. However, the proto functions that hci_bcm registers use mutexes and hence need to be able to sleep. In more detail: hci_uart_tty_receive() and hci_uart_dequeue() both acquire the rwlock, after which they call proto->recv() and proto->dequeue(), respectively. In the case of hci_bcm these point to bcm_recv() and bcm_dequeue(). The latter both acquire the bcm_device_lock, which is a mutex, so doing so results in a call to might_sleep(). But since we're holding a rwlock in hci_ldisc, that results in the following BUG (this for the dequeue case - a similar one for the receive case is omitted for brevity): BUG: sleeping function called from invalid context at kernel/locking/mutex.c in_atomic(): 1, irqs_disabled(): 0, pid: 7303, name: kworker/7:3 INFO: lockdep is turned off. CPU: 7 PID: 7303 Comm: kworker/7:3 Tainted: G W OE 4.13.2+ #17 Hardware name: Apple Inc. MacBookPro13,3/Mac-A5C67F76ED83108C, BIOS MBP133.8 Workqueue: events hci_uart_write_work [hci_uart] Call Trace: dump_stack+0x8e/0xd6 ___might_sleep+0x164/0x250 __might_sleep+0x4a/0x80 __mutex_lock+0x59/0xa00 ? lock_acquire+0xa3/0x1f0 ? lock_acquire+0xa3/0x1f0 ? hci_uart_write_work+0xd3/0x160 [hci_uart] mutex_lock_nested+0x1b/0x20 ? mutex_lock_nested+0x1b/0x20 bcm_dequeue+0x21/0xc0 [hci_uart] hci_uart_write_work+0xe6/0x160 [hci_uart] process_one_work+0x253/0x6a0 worker_thread+0x4d/0x3b0 kthread+0x133/0x150 We can't replace the mutex in hci_bcm, because there are other calls there that might sleep. Therefore this replaces the rwlock's in hci_ldisc with rw_semaphore's (which allow sleeping). This is a safer approach anyway as it reduces the restrictions on the proto callbacks. Also, because acquiring write-lock is very rare compared to acquiring the read-lock, the percpu variant of rw_semaphore is used. Lastly, because hci_uart_tx_wakeup() may be called from an IRQ context, we can't block (sleep) while trying acquire the read lock there, so we use the trylock variant. Signed-off-by: Ronald Tschalär <ronald@innovation.ch> Reviewed-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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see bug: 169701
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