kernel/linux.git/drivers/md/bcache/sysfs.c, branch v4.19.39

bcache: fix potential div-zero error of writeback_rate_p_term_inverse

2019-04-05T20:33:17+00:00

[ Upstream commit 5b5fd3c94eef69dcfaa8648198e54c92e5687d6d ] Current code already uses d_strtoul_nonzero() to convert input string to an unsigned integer, to make sure writeback_rate_p_term_inverse won't be zero value. But overflow may happen when converting input string to an unsigned integer value by d_strtoul_nonzero(), then dc->writeback_rate_p_term_inverse can still be set to 0 even if the sysfs file input value is not zero, e.g. 4294967296 (a.k.a UINT_MAX+1). If dc->writeback_rate_p_term_inverse is set to 0, it might cause a dev-zero error in following code from __update_writeback_rate(), int64_t proportional_scaled = div_s64(error, dc->writeback_rate_p_term_inverse); This patch replaces d_strtoul_nonzero() by sysfs_strtoul_clamp() and limit the value range in [1, UINT_MAX]. Then the unsigned integer overflow and dev-zero error can be avoided. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: fix potential div-zero error of writeback_rate_i_term_inverse

2019-04-05T20:33:09+00:00

[ Upstream commit c3b75a2199cdbfc1c335155fe143d842604b1baa ] dc->writeback_rate_i_term_inverse can be set via sysfs interface. It is in type unsigned int, and convert from input string by d_strtoul(). The problem is d_strtoul() does not check valid range of the input, if 4294967296 is written into sysfs file writeback_rate_i_term_inverse, an overflow of unsigned integer will happen and value 0 is set to dc->writeback_rate_i_term_inverse. In writeback.c:__update_writeback_rate(), there are following lines of code, integral_scaled = div_s64(dc->writeback_rate_integral, dc->writeback_rate_i_term_inverse); If dc->writeback_rate_i_term_inverse is set to 0 via sysfs interface, a div-zero error might be triggered in the above code. Therefore we need to add a range limitation in the sysfs interface, this is what this patch does, use sysfs_stroul_clamp() to replace d_strtoul() and restrict the input range in [1, UINT_MAX]. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: fix input overflow to sequential_cutoff

2019-04-05T20:33:09+00:00

[ Upstream commit 8c27a3953e92eb0b22dbb03d599f543a05f9574e ] People may set sequential_cutoff of a cached device via sysfs file, but current code does not check input value overflow. E.g. if value 4294967295 (UINT_MAX) is written to file sequential_cutoff, its value is 4GB, but if 4294967296 (UINT_MAX + 1) is written into, its value will be 0. This is an unexpected behavior. This patch replaces d_strtoi_h() by sysfs_strtoul_clamp() to convert input string to unsigned integer value, and limit its range in [0, UINT_MAX]. Then the input overflow can be fixed. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: fix input overflow to cache set sysfs file io_error_halflife

2019-04-05T20:33:09+00:00

[ Upstream commit a91fbda49f746119828f7e8ad0f0aa2ab0578f65 ] Cache set sysfs entry io_error_halflife is used to set c->error_decay. c->error_decay is in type unsigned int, and it is converted by strtoul_or_return(), therefore overflow to c->error_decay is possible for a large input value. This patch fixes the overflow by using strtoul_safe_clamp() to convert input string to an unsigned long value in range [0, UINT_MAX], then divides by 88 and set it to c->error_decay. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bcache: Populate writeback_rate_minimum attribute

2018-11-13T19:08:22+00:00

[ Upstream commit 7567c2a2ad9e80a2ce977eef535e64b61899633e ] Forgot to include the maintainers with my first email. Somewhere between Michael Lyle's original "bcache: PI controller for writeback rate V2" patch dated 07 Sep 2017 and 1d316e6 bcache: implement PI controller for writeback rate, the mapping of the writeback_rate_minimum attribute was dropped. Re-add the missing sysfs writeback_rate_minimum attribute mapping to "allow the user to specify a minimum rate at which dirty blocks are retired." Fixes: 1d316e6 ("bcache: implement PI controller for writeback rate") Signed-off-by: Ben Peddell Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

bcache: add static const prefix to char * array declarations

2018-08-11T21:46:42+00:00

This patch declares char * array with const prefix in sysfs.c, which is suggested by checkpatch.pl. Signed-off-by: Coly Li Reviewed-by: Shenghui Wang Signed-off-by: Jens Axboe

bcache: style fixes for lines over 80 characters

2018-08-11T21:46:41+00:00

This patch fixes the lines over 80 characters into more lines, to minimize warnings by checkpatch.pl. There are still some lines exceed 80 characters, but it is better to be a single line and I don't change them. Signed-off-by: Coly Li Reviewed-by: Shenghui Wang Signed-off-by: Jens Axboe

bcache: style fix to add a blank line after declarations

2018-08-11T21:46:41+00:00

Signed-off-by: Coly Li Reviewed-by: Shenghui Wang Signed-off-by: Jens Axboe

bcache: style fix to replace 'unsigned' by 'unsigned int'

2018-08-11T21:46:41+00:00

This patch fixes warning reported by checkpatch.pl by replacing 'unsigned' with 'unsigned int'. Signed-off-by: Coly Li Reviewed-by: Shenghui Wang Signed-off-by: Jens Axboe

bcache: fix error setting writeback_rate through sysfs interface

2018-08-10T18:18:47+00:00

Commit ea8c5356d390 ("bcache: set max writeback rate when I/O request is idle") changes struct bch_ratelimit member rate from uint32_t to atomic_long_t and uses atomic_long_set() in drivers/md/bcache/sysfs.c to set new writeback rate, after the input is converted from memory buf to long int by sysfs_strtoul_clamp(). The above change has a problem because there is an implicit return inside sysfs_strtoul_clamp() so the following atomic_long_set() won't be called. This error is detected by 0day system with following snipped smatch warnings: drivers/md/bcache/sysfs.c:271 __cached_dev_store() error: uninitialized symbol 'v'. 270 sysfs_strtoul_clamp(writeback_rate, v, 1, INT_MAX); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @271 atomic_long_set(&dc->writeback_rate.rate, v); This patch fixes the above error by using strtoul_safe_clamp() to convert the input buffer into a long int type result. Fixes: ea8c5356d390 ("bcache: set max writeback rate when I/O request is idle") Cc: Kai Krakow Cc: Stefan Priebe Signed-off-by: Coly Li Signed-off-by: Jens Axboe