summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2022-03-29 23:29:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-03-29 23:29:18 -0700
commitd888c83fcec75194a8a48ccd283953bdba7b2550 (patch)
tree66c5fd5d83bb02fcfbb678191ae34edbe0c4904d
parent965181d7ef7e1a863477536dc328c23a7ebc8a1d (diff)
fs: fix fd table size alignment properly
Jason Donenfeld reports that my commit 1c24a186398f ("fs: fd tables have to be multiples of BITS_PER_LONG") doesn't work, and the reason is an embarrassing brown-paper-bag bug. Yes, we want to align the number of fds to BITS_PER_LONG, and yes, the reason they might not be aligned is because the incoming 'max_fd' argument might not be aligned. But aligining the argument - while simple - will cause a "infinitely big" maxfd (eg NR_OPEN_MAX) to just overflow to zero. Which most definitely isn't what we want either. The obvious fix was always just to do the alignment last, but I had moved it earlier just to make the patch smaller and the code look simpler. Duh. It certainly made _me_ look simple. Fixes: 1c24a186398f ("fs: fd tables have to be multiples of BITS_PER_LONG") Reported-and-tested-by: Jason A. Donenfeld <Jason@zx2c4.com> Cc: Fedor Pchelkin <aissur0002@gmail.com> Cc: Alexey Khoroshilov <khoroshilov@ispras.ru> Cc: Christian Brauner <brauner@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/file.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/fs/file.c b/fs/file.c
index c01c29417ae6..ee9317346702 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -303,10 +303,9 @@ static unsigned int sane_fdtable_size(struct fdtable *fdt, unsigned int max_fds)
unsigned int count;
count = count_open_files(fdt);
- max_fds = ALIGN(max_fds, BITS_PER_LONG);
if (max_fds < NR_OPEN_DEFAULT)
max_fds = NR_OPEN_DEFAULT;
- return min(count, max_fds);
+ return ALIGN(min(count, max_fds), BITS_PER_LONG);
}
/*