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Jonas JelonekandJakub Kicinski
56d0885514
sfp->i2c_block_size is only assigned in sfp_sm_mod_probe(), which runs from the state machine timer after SFP_F_PRESENT has been set. Between those two points, sfp_module_eeprom() (the ethtool -m callback) gates only on SFP_F_PRESENT and can be entered with i2c_block_size still at its kzalloc'd value of 0. On a pure-I2C adapter, sfp_i2c_read() then issues an i2c_transfer() with msgs[1].len = 0 inside a loop that subtracts this_len from len each iteration; on adapters that succeed a zero-length read the loop never advances, spinning while holding rtnl_lock. This was previously addressed by initializing i2c_block_size in sfp_alloc() (commit813c2dd786), but the initialization was dropped when i2c_block_size was split from i2c_max_block_size. Initialize sfp->i2c_block_size from sfp->i2c_max_block_size in sfp_i2c_configure(), so the field is valid as soon as the adapter is known. sfp_sm_mod_probe() still reassigns it on each module insertion to recover from a per-module clamp to 1 (sfp_id_needs_byte_io). Fixes:7662abf4db("net: phy: sfp: Add support for SMBus module access") Cc: stable@vger.kernel.org Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com> Link: https://patch.msgid.link/20260528205242.971410-2-jelonek.jonas@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>