mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-25 10:19:47 +00:00
nfsd: Fix overflow causing non-working mounts on 1 TB machines
[ Upstream commit3b2d4dcf71
] Since commit10a68cdf10
(nfsd: fix performance-limiting session calculation) (Linux 5.1-rc1 and 4.19.31), shares from NFS servers with 1 TB of memory cannot be mounted anymore. The mount just hangs on the client. The gist of commit10a68cdf10
is the change below. -avail = clamp_t(int, avail, slotsize, avail/3); +avail = clamp_t(int, avail, slotsize, total_avail/3); Here are the macros. #define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <) #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi) `total_avail` is 8,434,659,328 on the 1 TB machine. `clamp_t()` casts the values to `int`, which for 32-bit integers can only hold values −2,147,483,648 (−2^31) through 2,147,483,647 (2^31 − 1). `avail` (in the function signature) is just 65536, so that no overflow was happening. Before the commit the assignment would result in 21845, and `num = 4`. When using `total_avail`, it is causing the assignment to be 18446744072226137429 (printed as %lu), and `num` is then 4164608182. My next guess is, that `nfsd_drc_mem_used` is then exceeded, and the server thinks there is no memory available any more for this client. Updating the arguments of `clamp_t()` and `min_t()` to `unsigned long` fixes the issue. Now, `avail = 65536` (before commit10a68cdf10
`avail = 21845`), but `num = 4` remains the same. Fixes:c54f24e338
(nfsd: fix performance-limiting session calculation) Cc: stable@vger.kernel.org Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
5226ab7b1d
commit
8e394a633b
1 changed files with 1 additions and 1 deletions
|
@ -1511,7 +1511,7 @@ static u32 nfsd4_get_drc_mem(struct nfsd4_channel_attrs *ca)
|
|||
* Never use more than a third of the remaining memory,
|
||||
* unless it's the only way to give this client a slot:
|
||||
*/
|
||||
avail = clamp_t(int, avail, slotsize, total_avail/3);
|
||||
avail = clamp_t(unsigned long, avail, slotsize, total_avail/3);
|
||||
num = min_t(int, num, avail / slotsize);
|
||||
nfsd_drc_mem_used += num * slotsize;
|
||||
spin_unlock(&nfsd_drc_lock);
|
||||
|
|
Loading…
Reference in a new issue