From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Zorro Lang <zlang@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linuxppc-dev@lists.ozlabs.org,
Nicholas Piggin <npiggin@gmail.com>
Subject: Re: [PATCH] powerpc/kuap: Allow kernel thread to access userspace after kthread_use_mm
Date: Fri, 05 Feb 2021 19:19:36 +0530 [thread overview]
Message-ID: <871rdur5e7.fsf@linux.ibm.com> (raw)
In-Reply-To: <20210205095820.GI14354@localhost.localdomain>
Zorro Lang <zlang@redhat.com> writes:
....
> ...
> [ 530.180466] run fstests generic/617 at 2021-02-05 03:41:10
> [ 530.707969] ------------[ cut here ]------------
> [ 530.708006] kernel BUG at arch/powerpc/include/asm/book3s/64/kup.h:207!
> [ 530.708013] Oops: Exception in kernel mode, sig: 5 [#1]
> [ 530.708018] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
> [ 530.708022] Modules linked in: bonding rfkill sunrpc uio_pdrv_genirq pseries_rng uio drm fuse drm_panel_orientation_quirks ip_tables xfs libcrc32c sd_mod t10_pi ibmvscsi ibmveth scsi_trans
> port_srp xts vmx_crypto
> [ 530.708049] CPU: 13 PID: 5587 Comm: io_wqe_worker-0 Not tainted 5.11.0-r
ok so we call current_thread_amr() with kthread.
commit ae33fb7b069ebb41e32f55ae397c887031e47472
Author: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Date: Fri Feb 5 19:11:49 2021 +0530
The other stack that matters is
...
[ 530.710838] CPU: 13 PID: 5587 Comm: io_wqe_worker-0 Tainted: G D 5.11.0-rc6+ #3
....
NIP [c0000000000aa0c8] pkey_access_permitted+0x28/0x90
LR [c0000000004b9278] gup_pte_range+0x188/0x420
--- interrupt: 700
[c00000001c4ef3f0] [0000000000000000] 0x0 (unreliable)
[c00000001c4ef490] [c0000000004bd39c] gup_pgd_range+0x3ac/0xa20
[c00000001c4ef5a0] [c0000000004bdd44] internal_get_user_pages_fast+0x334/0x410
[c00000001c4ef620] [c000000000852028] iov_iter_get_pages+0xf8/0x5c0
[c00000001c4ef6a0] [c0000000007da44c] bio_iov_iter_get_pages+0xec/0x700
[c00000001c4ef770] [c0000000006a325c] iomap_dio_bio_actor+0x2ac/0x4f0
[c00000001c4ef810] [c00000000069cd94] iomap_apply+0x2b4/0x740
[c00000001c4ef920] [c0000000006a38b8] __iomap_dio_rw+0x238/0x5c0
[c00000001c4ef9d0] [c0000000006a3c60] iomap_dio_rw+0x20/0x80
[c00000001c4ef9f0] [c008000001927a30] xfs_file_dio_aio_write+0x1f8/0x650 [xfs]
[c00000001c4efa60] [c0080000019284dc] xfs_file_write_iter+0xc4/0x130 [xfs]
[c00000001c4efa90] [c000000000669984] io_write+0x104/0x4b0
[c00000001c4efbb0] [c00000000066cea4] io_issue_sqe+0x3d4/0xf50
[c00000001c4efc60] [c000000000670200] io_wq_submit_work+0xb0/0x2f0
[c00000001c4efcb0] [c000000000674268] io_worker_handle_work+0x248/0x4a0
[c00000001c4efd30] [c0000000006746e8] io_wqe_worker+0x228/0x2a0
[c00000001c4efda0] [c00000000019d994] kthread+0x1b4/0x1c0
diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h
index 2064621ae7b6..21e59c1f0d67 100644
--- a/arch/powerpc/include/asm/book3s/64/kup.h
+++ b/arch/powerpc/include/asm/book3s/64/kup.h
@@ -204,14 +204,16 @@ DECLARE_STATIC_KEY_FALSE(uaccess_flush_key);
static inline u64 current_thread_amr(void)
{
- VM_BUG_ON(!current->thread.regs);
- return current->thread.regs->amr;
+ if (current->thread.regs)
+ return current->thread.regs->amr;
+ return 0;
}
static inline u64 current_thread_iamr(void)
{
- VM_BUG_ON(!current->thread.regs);
- return current->thread.regs->iamr;
+ if (current->thread.regs)
+ return current->thread.regs->iamr;
+ return 0;
}
#endif /* CONFIG_PPC_PKEY */
next prev parent reply other threads:[~2021-02-05 13:52 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-05 3:04 [PATCH] powerpc/kuap: Allow kernel thread to access userspace after kthread_use_mm Aneesh Kumar K.V
2021-02-05 9:58 ` Zorro Lang
2021-02-05 13:49 ` Aneesh Kumar K.V [this message]
2021-02-05 16:12 ` Zorro Lang
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