From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, ast@kernel.org, ebiggers@google.com,
gregkh@linuxfoundation.org, jeffv@google.com, jeyu@kernel.org,
keescook@chromium.org, linux-mm@kvack.org, mcgrof@kernel.org,
mm-commits@vger.kernel.org, neilb@suse.com,
stable@vger.kernel.org, torvalds@linux-foundation.org
Subject: [patch 27/35] fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once()
Date: Fri, 10 Apr 2020 14:33:47 -0700 [thread overview]
Message-ID: <20200410213347.RHoMObc5Z%akpm@linux-foundation.org> (raw)
In-Reply-To: <20200410143047.bf34a933ce1affdc042c7c80@linux-foundation.org>
From: Eric Biggers <ebiggers@google.com>
Subject: fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once()
After request_module(), nothing is stopping the module from being unloaded
until someone takes a reference to it via try_get_module().
The WARN_ONCE() in get_fs_type() is thus user-reachable, via userspace
running 'rmmod' concurrently.
Since WARN_ONCE() is for kernel bugs only, not for user-reachable
situations, downgrade this warning to pr_warn_once().
Keep it printed once only, since the intent of this warning is to detect a
bug in modprobe at boot time. Printing the warning more than once
wouldn't really provide any useful extra information.
Link: http://lkml.kernel.org/r/20200312202552.241885-3-ebiggers@kernel.org
Fixes: 41124db869b7 ("fs: warn in case userspace lied about modprobe return")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Jessica Yu <jeyu@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: NeilBrown <neilb@suse.com>
Cc: <stable@vger.kernel.org> [4.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
fs/filesystems.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/fs/filesystems.c~fs-filesystemsc-downgrade-user-reachable-warn_once-to-pr_warn_once
+++ a/fs/filesystems.c
@@ -272,7 +272,9 @@ struct file_system_type *get_fs_type(con
fs = __get_fs_type(name, len);
if (!fs && (request_module("fs-%.*s", len, name) == 0)) {
fs = __get_fs_type(name, len);
- WARN_ONCE(!fs, "request_module fs-%.*s succeeded, but still no fs?\n", len, name);
+ if (!fs)
+ pr_warn_once("request_module fs-%.*s succeeded, but still no fs?\n",
+ len, name);
}
if (dot && fs && !(fs->fs_flags & FS_HAS_SUBTYPE)) {
_
next prev parent reply other threads:[~2020-04-10 21:33 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-10 21:30 incoming Andrew Morton
2020-04-10 21:32 ` [patch 01/35] hfsplus: fix crash and filesystem corruption when deleting files Andrew Morton
2020-04-10 21:32 ` [patch 02/35] mm, memcg: do not high throttle allocators based on wraparound Andrew Morton
2020-04-10 21:32 ` [patch 03/35] mm, slab_common: fix a typo in comment "eariler"->"earlier" Andrew Morton
2020-04-10 21:32 ` [patch 04/35] docs: mm: slab.h: fix a broken cross-reference Andrew Morton
2020-04-10 21:32 ` [patch 05/35] mm/page_alloc.c: fix kernel-doc warning Andrew Morton
2020-04-10 21:32 ` [patch 06/35] mm/page_alloc: make pcpu_drain_mutex and pcpu_drain static Andrew Morton
2020-04-10 21:32 ` [patch 07/35] mm/gup: fix null pointer dereference detected by coverity Andrew Morton
2020-04-10 22:24 ` Linus Torvalds
2020-04-10 23:53 ` Peter Xu
2020-04-11 0:19 ` Linus Torvalds
2020-04-14 4:04 ` Miles Chen
2020-04-10 21:32 ` [patch 08/35] ocfs2: no need try to truncate file beyond i_size Andrew Morton
2020-04-10 21:32 ` [patch 09/35] mm: cma: NUMA node interface Andrew Morton
2020-04-10 21:32 ` [patch 10/35] mm: hugetlb: optionally allocate gigantic hugepages using cma Andrew Morton
2020-04-10 21:32 ` [patch 11/35] mm/mmap.c: initialize align_offset explicitly for vm_unmapped_area Andrew Morton
2020-04-10 21:32 ` [patch 12/35] mm/memory.c: refactor insert_page to prepare for batched-lock insert Andrew Morton
2020-04-10 21:32 ` [patch 13/35] mm: bring sparc pte_index() semantics inline with other platforms Andrew Morton
2020-04-10 21:32 ` [patch 14/35] mm: define pte_index as macro for x86 Andrew Morton
2020-04-10 21:33 ` [patch 15/35] mm/memory.c: add vm_insert_pages() Andrew Morton
2020-04-10 21:33 ` [patch 16/35] mm/vma: define a default value for VM_DATA_DEFAULT_FLAGS Andrew Morton
2020-04-10 21:33 ` [patch 17/35] mm/vma: introduce VM_ACCESS_FLAGS Andrew Morton
2020-04-10 21:33 ` [patch 18/35] mm/special: create generic fallbacks for pte_special() and pte_mkspecial() Andrew Morton
2020-04-10 21:33 ` [patch 19/35] mm/memory_hotplug: drop the flags field from struct mhp_restrictions Andrew Morton
2020-04-10 21:33 ` [patch 20/35] mm/memory_hotplug: rename mhp_restrictions to mhp_params Andrew Morton
2020-04-10 21:33 ` [patch 21/35] x86/mm: thread pgprot_t through init_memory_mapping() Andrew Morton
2020-04-10 21:33 ` [patch 22/35] x86/mm: introduce __set_memory_prot() Andrew Morton
2020-04-10 21:33 ` [patch 23/35] powerpc/mm: thread pgprot_t through create_section_mapping() Andrew Morton
2020-04-10 21:33 ` [patch 24/35] mm/memory_hotplug: add pgprot_t to mhp_params Andrew Morton
2020-04-10 21:33 ` [patch 25/35] mm/memremap: set caching mode for PCI P2PDMA memory to WC Andrew Morton
2020-04-10 21:33 ` [patch 26/35] kmod: make request_module() return an error when autoloading is disabled Andrew Morton
2020-04-10 21:33 ` Andrew Morton [this message]
2020-04-10 21:33 ` [patch 28/35] docs: admin-guide: document the kernel.modprobe sysctl Andrew Morton
2020-04-10 21:33 ` [patch 29/35] selftests: kmod: fix handling test numbers above 9 Andrew Morton
2020-04-10 21:33 ` [patch 30/35] selftests: kmod: test disabling module autoloading Andrew Morton
2020-04-10 21:34 ` [patch 31/35] change email address for Pali Rohár Andrew Morton
2020-04-10 21:44 ` Joe Perches
2020-04-10 21:34 ` [patch 32/35] drivers/dma/tegra20-apb-dma.c: fix platform_get_irq.cocci warnings Andrew Morton
2020-04-13 17:54 ` Jon Hunter
2020-04-10 21:34 ` [patch 33/35] fs/seq_file.c: seq_read(): add info message about buggy .next functions Andrew Morton
2020-04-10 21:34 ` [patch 34/35] kernel/gcov/fs.c: gcov_seq_next() should increase position index Andrew Morton
2020-04-10 21:34 ` [patch 35/35] ipc/util.c: sysvipc_find_ipc() " Andrew Morton
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