6.6-stable review patch. If anyone has any objections, please let me know.
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From: Muhammad Usama Anjum usama.anjum@collabora.com
commit 0aac13add26d546ac74c89d2883b3a5f0fbea039 upstream.
The "locked-in-memory size" limit per process can be non-multiple of page_size. The mmap() fails if we try to allocate locked-in-memory with same size as the allowed limit if it isn't multiple of the page_size because mmap() rounds off the memory size to be allocated to next multiple of page_size.
Fix this by flooring the length to be allocated with mmap() to the previous multiple of the page_size.
This was getting triggered on KernelCI regularly because of different ulimit settings which wasn't multiple of the page_size. Find logs here: https://linux.kernelci.org/test/plan/id/657654bd8e81e654fae13532/ The bug in was present from the time test was first added.
Link: https://lkml.kernel.org/r/20231214101931.1155586-1-usama.anjum@collabora.com Fixes: 76fe17ef588a ("secretmem: test: add basic selftest for memfd_secret(2)") Signed-off-by: Muhammad Usama Anjum usama.anjum@collabora.com Reported-by: "kernelci.org bot" bot@kernelci.org Closes: https://linux.kernelci.org/test/plan/id/657654bd8e81e654fae13532/ Cc: "James E.J. Bottomley" James.Bottomley@HansenPartnership.com Cc: Mike Rapoport (IBM) rppt@kernel.org Cc: Shuah Khan shuah@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/mm/memfd_secret.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/tools/testing/selftests/mm/memfd_secret.c +++ b/tools/testing/selftests/mm/memfd_secret.c @@ -62,6 +62,9 @@ static void test_mlock_limit(int fd) char *mem;
len = mlock_limit_cur; + if (len % page_size != 0) + len = (len/page_size) * page_size; + mem = mmap(NULL, len, prot, mode, fd, 0); if (mem == MAP_FAILED) { fail("unable to mmap secret memory\n");